import java.util.*;
import java.io.*;



public class Main{
    static boolean[] vis;                       //line 74 and 91 hasElement ans pth_fnd
    static int MOD=1000000007;
    //
    static int[] ans;
    static int cnt;
    static long set1=0,set2=0;
    //
    public static void main(String[] args) throws IOException{
        // long sttm=System.currentTimeMillis();
        FastReader sc=new FastReader();
        OutputStream out=new BufferedOutputStream(System.out);
        int s=sc.nextInt(),w=sc.nextInt();
        if(w>=s){
            System.out.println("unsafe");
        }
        else{
            System.out.println("safe");
        }
        

    }


    public static long pow(long n,long k){                 //n-pow(k)
        if(k==1){
            return n%MOD;
        }
        if(k==0){
            return 1;
        }
        long val=pow(n,k/2)%MOD;
        if(k%2==0)return ((val%MOD)*(val%MOD))%MOD;
        else return (((val*val)%MOD)*n)%MOD;
    }


    public static ArrayList<Integer> lcm(int num){
        ArrayList<Integer> arrl=new ArrayList<Integer>();
        while(num%2==0){
            arrl.add(2);
            num/=2;
        }
        for(int i=3;i*i<=num;i+=2){
            while(num%i==0){
                arrl.add(i);
                num/=i;
            }
        }
        if(num>2){
            arrl.add(num);
        }
        return arrl;
    }


    static long m=998244353l;
    static long modInverse(long a,long m) 
    { 
        long m0 = m;
        long y = 0l, x = 1l; 
  
        if (m == 1) 
            return 0l; 
  
        while (a > 1) 
        { 
  
            long q = a / m; 
  
            long t = m; 
  
            m = a % m; 
            a = t; 
            t = y; 
  
            y = x - q * y; 
            x = t; 
        } 
        if (x < 0) 
            x += m0; 
  
        return x; 
    }


    public static int num_fact(int num){
        ArrayList<Integer> arr=new ArrayList<Integer>();
        int cnt=0;
        for(int i=1;i*i<=num;i++){
            if(num%i==0){
                if(i*i==num){
                    cnt+=1;
                }
                else{
                    cnt+=2;
                }
            }
        }
        return cnt;
    }


    public static void sort_inc(int[][] arr,int col){        //change dimention if req
        Arrays.sort(arr, new Comparator<int[]>() {
            public int compare(final int[] entry1,final int[] entry2) { 
                if (entry1[col] > entry2[col])              //this is for inc
                    return 1; 
                else if(entry1[col]==entry2[col])
                    return 0;
                else
                    return -1; 
            }
        });
    }


    public static boolean prime(int n){
        for(int i=2;i*i<=n;i++){
            if(n%i==0){
                return false;
            }
        }
        return true;
    }


    static long gcd(long a, long b) 
	{ 
	if (b == 0) 
		return a; 
	return gcd(b, a % b); 
	} 
}


class FastReader{ 
    BufferedReader br; 
    StringTokenizer st; 

    public FastReader(){ 
        br = new BufferedReader(new
                 InputStreamReader(System.in)); 
    } 
  
    String next(){ 
        while (st == null || !st.hasMoreElements()){ 
            try{ 
                st = new StringTokenizer(br.readLine()); 
            } 
            catch (IOException  e){ 
                e.printStackTrace(); 
            } 
        } 
        return st.nextToken(); 
    } 
  
    int nextInt(){ 
        return Integer.parseInt(next()); 
    } 
  
    long nextLong(){ 
        return Long.parseLong(next()); 
    }
  
    double nextDouble(){ 
        return Double.parseDouble(next()); 
    }
  
    String nextLine(){ 
        String str = ""; 
        try{ 
            str = br.readLine(); 
        }
        catch (IOException e){ 
            e.printStackTrace(); 
        }
        return str; 
    }
} Comparator<int[]>() {
            public int compare(final int[] entry1,final int[] entry2) { 
                if (entry1[col] > entry2[col])              //this is for inc
                    return 1; 
                else if(entry1[col]==entry2[col])
                    return 0;
                else
                    return -1; 
            }
        } public int compare(final int[] entry1,final int[] entry2) { 
                if (entry1[col] > entry2[col])              //this is for inc
                    return 1; 
                else if(entry1[col]==entry2[col])
                    return 0;
                else
                    return -1; 
            } compare { 
                if (entry1[col] > entry2[col])              //this is for inc
                    return 1; 
                else if(entry1[col]==entry2[col])
                    return 0;
                else
                    return -1; 
            } if (entry1[col] > entry2[col])              //this is for inc
                    return 1; 
                else if(entry1[col]==entry2[col])
                    return 0;
                else
                    return -1; entry1[col] > entry2[col] entry1[col] entry1 col entry2[col] entry2 col return 1; 1 if(entry1[col]==entry2[col])
                    return 0;
                else
                    return -1; entry1[col]==entry2[col] entry1[col] entry1 col entry2[col] entry2 col return 0; 0 return -1; -1 1 final int[] entry1 entry1 final int[] entry2 entry2 import java.util.*; util.* java import java.io.*; io.* java public class Main{
    static boolean[] vis;                       //line 74 and 91 hasElement ans pth_fnd
    static int MOD=1000000007;
    //
    static int[] ans;
    static int cnt;
    static long set1=0,set2=0;
    //
    public static void main(String[] args) throws IOException{
        // long sttm=System.currentTimeMillis();
        FastReader sc=new FastReader();
        OutputStream out=new BufferedOutputStream(System.out);
        int s=sc.nextInt(),w=sc.nextInt();
        if(w>=s){
            System.out.println("unsafe");
        }
        else{
            System.out.println("safe");
        }
        

    }


    public static long pow(long n,long k){                 //n-pow(k)
        if(k==1){
            return n%MOD;
        }
        if(k==0){
            return 1;
        }
        long val=pow(n,k/2)%MOD;
        if(k%2==0)return ((val%MOD)*(val%MOD))%MOD;
        else return (((val*val)%MOD)*n)%MOD;
    }


    public static ArrayList<Integer> lcm(int num){
        ArrayList<Integer> arrl=new ArrayList<Integer>();
        while(num%2==0){
            arrl.add(2);
            num/=2;
        }
        for(int i=3;i*i<=num;i+=2){
            while(num%i==0){
                arrl.add(i);
                num/=i;
            }
        }
        if(num>2){
            arrl.add(num);
        }
        return arrl;
    }


    static long m=998244353l;
    static long modInverse(long a,long m) 
    { 
        long m0 = m;
        long y = 0l, x = 1l; 
  
        if (m == 1) 
            return 0l; 
  
        while (a > 1) 
        { 
  
            long q = a / m; 
  
            long t = m; 
  
            m = a % m; 
            a = t; 
            t = y; 
  
            y = x - q * y; 
            x = t; 
        } 
        if (x < 0) 
            x += m0; 
  
        return x; 
    }


    public static int num_fact(int num){
        ArrayList<Integer> arr=new ArrayList<Integer>();
        int cnt=0;
        for(int i=1;i*i<=num;i++){
            if(num%i==0){
                if(i*i==num){
                    cnt+=1;
                }
                else{
                    cnt+=2;
                }
            }
        }
        return cnt;
    }


    public static void sort_inc(int[][] arr,int col){        //change dimention if req
        Arrays.sort(arr, new Comparator<int[]>() {
            public int compare(final int[] entry1,final int[] entry2) { 
                if (entry1[col] > entry2[col])              //this is for inc
                    return 1; 
                else if(entry1[col]==entry2[col])
                    return 0;
                else
                    return -1; 
            }
        });
    }


    public static boolean prime(int n){
        for(int i=2;i*i<=n;i++){
            if(n%i==0){
                return false;
            }
        }
        return true;
    }


    static long gcd(long a, long b) 
	{ 
	if (b == 0) 
		return a; 
	return gcd(b, a % b); 
	} 
} Main static boolean[] vis;                       //line 74 and 91 hasElement ans pth_fnd vis static int MOD=1000000007; MOD 1000000007 //
    static int[] ans; ans static int cnt; cnt static long set1=0 set1 0 set2=0; set2 0 static long m=998244353l; m 998244353l //
    public static void main(String[] args) throws IOException{
        // long sttm=System.currentTimeMillis();
        FastReader sc=new FastReader();
        OutputStream out=new BufferedOutputStream(System.out);
        int s=sc.nextInt(),w=sc.nextInt();
        if(w>=s){
            System.out.println("unsafe");
        }
        else{
            System.out.println("safe");
        }
        

    } main {
        // long sttm=System.currentTimeMillis();
        FastReader sc=new FastReader();
        OutputStream out=new BufferedOutputStream(System.out);
        int s=sc.nextInt(),w=sc.nextInt();
        if(w>=s){
            System.out.println("unsafe");
        }
        else{
            System.out.println("safe");
        }
        

    } FastReader sc=new FastReader(); sc new FastReader() OutputStream out=new BufferedOutputStream(System.out); out new BufferedOutputStream(System.out) int s=sc.nextInt() s sc.nextInt() sc.nextInt sc w=sc.nextInt(); w sc.nextInt() sc.nextInt sc if(w>=s){
            System.out.println("unsafe");
        }
        else{
            System.out.println("safe");
        } w>=s w s {
            System.out.println("unsafe");
        } System.out.println("unsafe") System.out.println System.out System System.out "unsafe" {
            System.out.println("safe");
        } System.out.println("safe") System.out.println System.out System System.out "safe" String[] args args public static long pow(long n,long k){                 //n-pow(k)
        if(k==1){
            return n%MOD;
        }
        if(k==0){
            return 1;
        }
        long val=pow(n,k/2)%MOD;
        if(k%2==0)return ((val%MOD)*(val%MOD))%MOD;
        else return (((val*val)%MOD)*n)%MOD;
    } pow {                 //n-pow(k)
        if(k==1){
            return n%MOD;
        }
        if(k==0){
            return 1;
        }
        long val=pow(n,k/2)%MOD;
        if(k%2==0)return ((val%MOD)*(val%MOD))%MOD;
        else return (((val*val)%MOD)*n)%MOD;
    } if(k==1){
            return n%MOD;
        } k==1 k 1 {
            return n%MOD;
        } return n%MOD; n%MOD n MOD if(k==0){
            return 1;
        } k==0 k 0 {
            return 1;
        } return 1; 1 long val=pow(n,k/2)%MOD; val pow(n,k/2)%MOD pow(n,k/2) pow n k/2 k 2 MOD if(k%2==0)return ((val%MOD)*(val%MOD))%MOD;
        else return (((val*val)%MOD)*n)%MOD; k%2==0 k%2 k 2 0 return ((val%MOD)*(val%MOD))%MOD; ((val%MOD)*(val%MOD))%MOD ((val%MOD)*(val%MOD)) (val%MOD) val MOD (val%MOD) val MOD MOD return (((val*val)%MOD)*n)%MOD; (((val*val)%MOD)*n)%MOD (((val*val)%MOD)*n) ((val*val)%MOD) (val*val) val val MOD n MOD long n n long k k public static ArrayList<Integer> lcm(int num){
        ArrayList<Integer> arrl=new ArrayList<Integer>();
        while(num%2==0){
            arrl.add(2);
            num/=2;
        }
        for(int i=3;i*i<=num;i+=2){
            while(num%i==0){
                arrl.add(i);
                num/=i;
            }
        }
        if(num>2){
            arrl.add(num);
        }
        return arrl;
    } lcm {
        ArrayList<Integer> arrl=new ArrayList<Integer>();
        while(num%2==0){
            arrl.add(2);
            num/=2;
        }
        for(int i=3;i*i<=num;i+=2){
            while(num%i==0){
                arrl.add(i);
                num/=i;
            }
        }
        if(num>2){
            arrl.add(num);
        }
        return arrl;
    } ArrayList<Integer> arrl=new ArrayList<Integer>(); arrl new ArrayList<Integer>() while(num%2==0){
            arrl.add(2);
            num/=2;
        } num%2==0 num%2 num 2 0 {
            arrl.add(2);
            num/=2;
        } arrl.add(2) arrl.add arrl 2 num/=2 num 2 for(int i=3;i*i<=num;i+=2){
            while(num%i==0){
                arrl.add(i);
                num/=i;
            }
        } int i=3; int i=3; i 3 i*i<=num i*i i i num i+=2 i+=2 i 2 {
            while(num%i==0){
                arrl.add(i);
                num/=i;
            }
        } {
            while(num%i==0){
                arrl.add(i);
                num/=i;
            }
        } while(num%i==0){
                arrl.add(i);
                num/=i;
            } num%i==0 num%i num i 0 {
                arrl.add(i);
                num/=i;
            } arrl.add(i) arrl.add arrl i num/=i num i if(num>2){
            arrl.add(num);
        } num>2 num 2 {
            arrl.add(num);
        } arrl.add(num) arrl.add arrl num return arrl; arrl int num num static long modInverse(long a,long m) 
    { 
        long m0 = m;
        long y = 0l, x = 1l; 
  
        if (m == 1) 
            return 0l; 
  
        while (a > 1) 
        { 
  
            long q = a / m; 
  
            long t = m; 
  
            m = a % m; 
            a = t; 
            t = y; 
  
            y = x - q * y; 
            x = t; 
        } 
        if (x < 0) 
            x += m0; 
  
        return x; 
    } modInverse { 
        long m0 = m;
        long y = 0l, x = 1l; 
  
        if (m == 1) 
            return 0l; 
  
        while (a > 1) 
        { 
  
            long q = a / m; 
  
            long t = m; 
  
            m = a % m; 
            a = t; 
            t = y; 
  
            y = x - q * y; 
            x = t; 
        } 
        if (x < 0) 
            x += m0; 
  
        return x; 
    } long m0 = m; m0 m long y = 0l y 0l x = 1l; x 1l if (m == 1) 
            return 0l; m == 1 m 1 return 0l; 0l while (a > 1) 
        { 
  
            long q = a / m; 
  
            long t = m; 
  
            m = a % m; 
            a = t; 
            t = y; 
  
            y = x - q * y; 
            x = t; 
        } a > 1 a 1 { 
  
            long q = a / m; 
  
            long t = m; 
  
            m = a % m; 
            a = t; 
            t = y; 
  
            y = x - q * y; 
            x = t; 
        } long q = a / m; q a / m a m long t = m; t m m = a % m m a % m a m a = t a t t = y t y y = x - q * y y x - q * y x q * y q y x = t x t if (x < 0) 
            x += m0; x < 0 x 0 x += m0 x m0 return x; x long a a long m m public static int num_fact(int num){
        ArrayList<Integer> arr=new ArrayList<Integer>();
        int cnt=0;
        for(int i=1;i*i<=num;i++){
            if(num%i==0){
                if(i*i==num){
                    cnt+=1;
                }
                else{
                    cnt+=2;
                }
            }
        }
        return cnt;
    } num_fact {
        ArrayList<Integer> arr=new ArrayList<Integer>();
        int cnt=0;
        for(int i=1;i*i<=num;i++){
            if(num%i==0){
                if(i*i==num){
                    cnt+=1;
                }
                else{
                    cnt+=2;
                }
            }
        }
        return cnt;
    } ArrayList<Integer> arr=new ArrayList<Integer>(); arr new ArrayList<Integer>() int cnt=0; cnt 0 for(int i=1;i*i<=num;i++){
            if(num%i==0){
                if(i*i==num){
                    cnt+=1;
                }
                else{
                    cnt+=2;
                }
            }
        } int i=1; int i=1; i 1 i*i<=num i*i i i num i++ i++ i {
            if(num%i==0){
                if(i*i==num){
                    cnt+=1;
                }
                else{
                    cnt+=2;
                }
            }
        } {
            if(num%i==0){
                if(i*i==num){
                    cnt+=1;
                }
                else{
                    cnt+=2;
                }
            }
        } if(num%i==0){
                if(i*i==num){
                    cnt+=1;
                }
                else{
                    cnt+=2;
                }
            } num%i==0 num%i num i 0 {
                if(i*i==num){
                    cnt+=1;
                }
                else{
                    cnt+=2;
                }
            } if(i*i==num){
                    cnt+=1;
                }
                else{
                    cnt+=2;
                } i*i==num i*i i i num {
                    cnt+=1;
                } cnt+=1 cnt 1 {
                    cnt+=2;
                } cnt+=2 cnt 2 return cnt; cnt int num num public static void sort_inc(int[][] arr,int col){        //change dimention if req
        Arrays.sort(arr, new Comparator<int[]>() {
            public int compare(final int[] entry1,final int[] entry2) { 
                if (entry1[col] > entry2[col])              //this is for inc
                    return 1; 
                else if(entry1[col]==entry2[col])
                    return 0;
                else
                    return -1; 
            }
        });
    } sort_inc {        //change dimention if req
        Arrays.sort(arr, new Comparator<int[]>() {
            public int compare(final int[] entry1,final int[] entry2) { 
                if (entry1[col] > entry2[col])              //this is for inc
                    return 1; 
                else if(entry1[col]==entry2[col])
                    return 0;
                else
                    return -1; 
            }
        });
    } Arrays.sort(arr, new Comparator<int[]>() {
            public int compare(final int[] entry1,final int[] entry2) { 
                if (entry1[col] > entry2[col])              //this is for inc
                    return 1; 
                else if(entry1[col]==entry2[col])
                    return 0;
                else
                    return -1; 
            }
        }) Arrays.sort Arrays arr new Comparator<int[]>() {
            public int compare(final int[] entry1,final int[] entry2) { 
                if (entry1[col] > entry2[col])              //this is for inc
                    return 1; 
                else if(entry1[col]==entry2[col])
                    return 0;
                else
                    return -1; 
            }
        } int[][] arr arr int col col public static boolean prime(int n){
        for(int i=2;i*i<=n;i++){
            if(n%i==0){
                return false;
            }
        }
        return true;
    } prime {
        for(int i=2;i*i<=n;i++){
            if(n%i==0){
                return false;
            }
        }
        return true;
    } for(int i=2;i*i<=n;i++){
            if(n%i==0){
                return false;
            }
        } int i=2; int i=2; i 2 i*i<=n i*i i i n i++ i++ i {
            if(n%i==0){
                return false;
            }
        } {
            if(n%i==0){
                return false;
            }
        } if(n%i==0){
                return false;
            } n%i==0 n%i n i 0 {
                return false;
            } return false; false return true; true int n n static long gcd(long a, long b) 
	{ 
	if (b == 0) 
		return a; 
	return gcd(b, a % b); 
	} gcd { 
	if (b == 0) 
		return a; 
	return gcd(b, a % b); 
	} if (b == 0) 
		return a; b == 0 b 0 return a; a return gcd(b, a % b); gcd(b, a % b) gcd b a % b a b long a a long b b class FastReader{ 
    BufferedReader br; 
    StringTokenizer st; 

    public FastReader(){ 
        br = new BufferedReader(new
                 InputStreamReader(System.in)); 
    } 
  
    String next(){ 
        while (st == null || !st.hasMoreElements()){ 
            try{ 
                st = new StringTokenizer(br.readLine()); 
            } 
            catch (IOException  e){ 
                e.printStackTrace(); 
            } 
        } 
        return st.nextToken(); 
    } 
  
    int nextInt(){ 
        return Integer.parseInt(next()); 
    } 
  
    long nextLong(){ 
        return Long.parseLong(next()); 
    }
  
    double nextDouble(){ 
        return Double.parseDouble(next()); 
    }
  
    String nextLine(){ 
        String str = ""; 
        try{ 
            str = br.readLine(); 
        }
        catch (IOException e){ 
            e.printStackTrace(); 
        }
        return str; 
    }
} FastReader BufferedReader br; br StringTokenizer st; st public FastReader(){ 
        br = new BufferedReader(new
                 InputStreamReader(System.in)); 
    } FastReader { 
        br = new BufferedReader(new
                 InputStreamReader(System.in)); 
    } br = new BufferedReader(new
                 InputStreamReader(System.in)) br new BufferedReader(new
                 InputStreamReader(System.in)) String next(){ 
        while (st == null || !st.hasMoreElements()){ 
            try{ 
                st = new StringTokenizer(br.readLine()); 
            } 
            catch (IOException  e){ 
                e.printStackTrace(); 
            } 
        } 
        return st.nextToken(); 
    } next { 
        while (st == null || !st.hasMoreElements()){ 
            try{ 
                st = new StringTokenizer(br.readLine()); 
            } 
            catch (IOException  e){ 
                e.printStackTrace(); 
            } 
        } 
        return st.nextToken(); 
    } while (st == null || !st.hasMoreElements()){ 
            try{ 
                st = new StringTokenizer(br.readLine()); 
            } 
            catch (IOException  e){ 
                e.printStackTrace(); 
            } 
        } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st { 
            try{ 
                st = new StringTokenizer(br.readLine()); 
            } 
            catch (IOException  e){ 
                e.printStackTrace(); 
            } 
        } try{ 
                st = new StringTokenizer(br.readLine()); 
            } 
            catch (IOException  e){ 
                e.printStackTrace(); 
            } catch (IOException  e){ 
                e.printStackTrace(); 
            } IOException  e { 
                e.printStackTrace(); 
            } e.printStackTrace() e.printStackTrace e { 
                st = new StringTokenizer(br.readLine()); 
            } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt(){ 
        return Integer.parseInt(next()); 
    } nextInt { 
        return Integer.parseInt(next()); 
    } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong(){ 
        return Long.parseLong(next()); 
    } nextLong { 
        return Long.parseLong(next()); 
    } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble(){ 
        return Double.parseDouble(next()); 
    } nextDouble { 
        return Double.parseDouble(next()); 
    } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine(){ 
        String str = ""; 
        try{ 
            str = br.readLine(); 
        }
        catch (IOException e){ 
            e.printStackTrace(); 
        }
        return str; 
    } nextLine { 
        String str = ""; 
        try{ 
            str = br.readLine(); 
        }
        catch (IOException e){ 
            e.printStackTrace(); 
        }
        return str; 
    } String str = ""; str "" try{ 
            str = br.readLine(); 
        }
        catch (IOException e){ 
            e.printStackTrace(); 
        } catch (IOException e){ 
            e.printStackTrace(); 
        } IOException e { 
            e.printStackTrace(); 
        } e.printStackTrace() e.printStackTrace e { 
            str = br.readLine(); 
        } str = br.readLine() str br.readLine() br.readLine br return str; str public class Main{
    static boolean[] vis;                       //line 74 and 91 hasElement ans pth_fnd
    static int MOD=1000000007;
    //
    static int[] ans;
    static int cnt;
    static long set1=0,set2=0;
    //
    public static void main(String[] args) throws IOException{
        // long sttm=System.currentTimeMillis();
        FastReader sc=new FastReader();
        OutputStream out=new BufferedOutputStream(System.out);
        int s=sc.nextInt(),w=sc.nextInt();
        if(w>=s){
            System.out.println("unsafe");
        }
        else{
            System.out.println("safe");
        }
        

    }


    public static long pow(long n,long k){                 //n-pow(k)
        if(k==1){
            return n%MOD;
        }
        if(k==0){
            return 1;
        }
        long val=pow(n,k/2)%MOD;
        if(k%2==0)return ((val%MOD)*(val%MOD))%MOD;
        else return (((val*val)%MOD)*n)%MOD;
    }


    public static ArrayList<Integer> lcm(int num){
        ArrayList<Integer> arrl=new ArrayList<Integer>();
        while(num%2==0){
            arrl.add(2);
            num/=2;
        }
        for(int i=3;i*i<=num;i+=2){
            while(num%i==0){
                arrl.add(i);
                num/=i;
            }
        }
        if(num>2){
            arrl.add(num);
        }
        return arrl;
    }


    static long m=998244353l;
    static long modInverse(long a,long m) 
    { 
        long m0 = m;
        long y = 0l, x = 1l; 
  
        if (m == 1) 
            return 0l; 
  
        while (a > 1) 
        { 
  
            long q = a / m; 
  
            long t = m; 
  
            m = a % m; 
            a = t; 
            t = y; 
  
            y = x - q * y; 
            x = t; 
        } 
        if (x < 0) 
            x += m0; 
  
        return x; 
    }


    public static int num_fact(int num){
        ArrayList<Integer> arr=new ArrayList<Integer>();
        int cnt=0;
        for(int i=1;i*i<=num;i++){
            if(num%i==0){
                if(i*i==num){
                    cnt+=1;
                }
                else{
                    cnt+=2;
                }
            }
        }
        return cnt;
    }


    public static void sort_inc(int[][] arr,int col){        //change dimention if req
        Arrays.sort(arr, new Comparator<int[]>() {
            public int compare(final int[] entry1,final int[] entry2) { 
                if (entry1[col] > entry2[col])              //this is for inc
                    return 1; 
                else if(entry1[col]==entry2[col])
                    return 0;
                else
                    return -1; 
            }
        });
    }


    public static boolean prime(int n){
        for(int i=2;i*i<=n;i++){
            if(n%i==0){
                return false;
            }
        }
        return true;
    }


    static long gcd(long a, long b) 
	{ 
	if (b == 0) 
		return a; 
	return gcd(b, a % b); 
	} 
} public class Main{
    static boolean[] vis;                       //line 74 and 91 hasElement ans pth_fnd
    static int MOD=1000000007;
    //
    static int[] ans;
    static int cnt;
    static long set1=0,set2=0;
    //
    public static void main(String[] args) throws IOException{
        // long sttm=System.currentTimeMillis();
        FastReader sc=new FastReader();
        OutputStream out=new BufferedOutputStream(System.out);
        int s=sc.nextInt(),w=sc.nextInt();
        if(w>=s){
            System.out.println("unsafe");
        }
        else{
            System.out.println("safe");
        }
        

    }


    public static long pow(long n,long k){                 //n-pow(k)
        if(k==1){
            return n%MOD;
        }
        if(k==0){
            return 1;
        }
        long val=pow(n,k/2)%MOD;
        if(k%2==0)return ((val%MOD)*(val%MOD))%MOD;
        else return (((val*val)%MOD)*n)%MOD;
    }


    public static ArrayList<Integer> lcm(int num){
        ArrayList<Integer> arrl=new ArrayList<Integer>();
        while(num%2==0){
            arrl.add(2);
            num/=2;
        }
        for(int i=3;i*i<=num;i+=2){
            while(num%i==0){
                arrl.add(i);
                num/=i;
            }
        }
        if(num>2){
            arrl.add(num);
        }
        return arrl;
    }


    static long m=998244353l;
    static long modInverse(long a,long m) 
    { 
        long m0 = m;
        long y = 0l, x = 1l; 
  
        if (m == 1) 
            return 0l; 
  
        while (a > 1) 
        { 
  
            long q = a / m; 
  
            long t = m; 
  
            m = a % m; 
            a = t; 
            t = y; 
  
            y = x - q * y; 
            x = t; 
        } 
        if (x < 0) 
            x += m0; 
  
        return x; 
    }


    public static int num_fact(int num){
        ArrayList<Integer> arr=new ArrayList<Integer>();
        int cnt=0;
        for(int i=1;i*i<=num;i++){
            if(num%i==0){
                if(i*i==num){
                    cnt+=1;
                }
                else{
                    cnt+=2;
                }
            }
        }
        return cnt;
    }


    public static void sort_inc(int[][] arr,int col){        //change dimention if req
        Arrays.sort(arr, new Comparator<int[]>() {
            public int compare(final int[] entry1,final int[] entry2) { 
                if (entry1[col] > entry2[col])              //this is for inc
                    return 1; 
                else if(entry1[col]==entry2[col])
                    return 0;
                else
                    return -1; 
            }
        });
    }


    public static boolean prime(int n){
        for(int i=2;i*i<=n;i++){
            if(n%i==0){
                return false;
            }
        }
        return true;
    }


    static long gcd(long a, long b) 
	{ 
	if (b == 0) 
		return a; 
	return gcd(b, a % b); 
	} 
} Main
import java.util.*;
import java.io.*;



public class Main{
    static boolean[] vis;                       //line 74 and 91 hasElement ans pth_fnd
    static int MOD=1000000007;
    //
    static int[] ans;
    static int cnt;
    static long set1=0,set2=0;
    //
    public static void main(String[] args) throws IOException{
        // long sttm=System.currentTimeMillis();
        FastReader sc=new FastReader();
        OutputStream out=new BufferedOutputStream(System.out);
        int s=sc.nextInt(),w=sc.nextInt();
        if(w>=s){
            System.out.println("unsafe");
        }
        else{
            System.out.println("safe");
        }
        

    }


    public static long pow(long n,long k){                 //n-pow(k)
        if(k==1){
            return n%MOD;
        }
        if(k==0){
            return 1;
        }
        long val=pow(n,k/2)%MOD;
        if(k%2==0)return ((val%MOD)*(val%MOD))%MOD;
        else return (((val*val)%MOD)*n)%MOD;
    }


    public static ArrayList<Integer> lcm(int num){
        ArrayList<Integer> arrl=new ArrayList<Integer>();
        while(num%2==0){
            arrl.add(2);
            num/=2;
        }
        for(int i=3;i*i<=num;i+=2){
            while(num%i==0){
                arrl.add(i);
                num/=i;
            }
        }
        if(num>2){
            arrl.add(num);
        }
        return arrl;
    }


    static long m=998244353l;
    static long modInverse(long a,long m) 
    { 
        long m0 = m;
        long y = 0l, x = 1l; 
  
        if (m == 1) 
            return 0l; 
  
        while (a > 1) 
        { 
  
            long q = a / m; 
  
            long t = m; 
  
            m = a % m; 
            a = t; 
            t = y; 
  
            y = x - q * y; 
            x = t; 
        } 
        if (x < 0) 
            x += m0; 
  
        return x; 
    }


    public static int num_fact(int num){
        ArrayList<Integer> arr=new ArrayList<Integer>();
        int cnt=0;
        for(int i=1;i*i<=num;i++){
            if(num%i==0){
                if(i*i==num){
                    cnt+=1;
                }
                else{
                    cnt+=2;
                }
            }
        }
        return cnt;
    }


    public static void sort_inc(int[][] arr,int col){        //change dimention if req
        Arrays.sort(arr, new Comparator<int[]>() {
            public int compare(final int[] entry1,final int[] entry2) { 
                if (entry1[col] > entry2[col])              //this is for inc
                    return 1; 
                else if(entry1[col]==entry2[col])
                    return 0;
                else
                    return -1; 
            }
        });
    }


    public static boolean prime(int n){
        for(int i=2;i*i<=n;i++){
            if(n%i==0){
                return false;
            }
        }
        return true;
    }


    static long gcd(long a, long b) 
	{ 
	if (b == 0) 
		return a; 
	return gcd(b, a % b); 
	} 
}


class FastReader{ 
    BufferedReader br; 
    StringTokenizer st; 

    public FastReader(){ 
        br = new BufferedReader(new
                 InputStreamReader(System.in)); 
    } 
  
    String next(){ 
        while (st == null || !st.hasMoreElements()){ 
            try{ 
                st = new StringTokenizer(br.readLine()); 
            } 
            catch (IOException  e){ 
                e.printStackTrace(); 
            } 
        } 
        return st.nextToken(); 
    } 
  
    int nextInt(){ 
        return Integer.parseInt(next()); 
    } 
  
    long nextLong(){ 
        return Long.parseLong(next()); 
    }
  
    double nextDouble(){ 
        return Double.parseDouble(next()); 
    }
  
    String nextLine(){ 
        String str = ""; 
        try{ 
            str = br.readLine(); 
        }
        catch (IOException e){ 
            e.printStackTrace(); 
        }
        return str; 
    }
}