import java.io.*;
import java.lang.*;
import java.util.*;
public class Main{  
    public static void main(String[] args) throws IOException{
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        String[] str=br.readLine().split(" ");
        long S=Long.parseLong(str[0]);
        long W=Long.parseLong(str[1]);
        if(W>=S) System.out.println("unsafe");
        else System.out.println("safe");
        }
    } import java.io.*; io.* java import java.lang.*; lang.* java import java.util.*; util.* java public class Main{  
    public static void main(String[] args) throws IOException{
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        String[] str=br.readLine().split(" ");
        long S=Long.parseLong(str[0]);
        long W=Long.parseLong(str[1]);
        if(W>=S) System.out.println("unsafe");
        else System.out.println("safe");
        }
    } Main public static void main(String[] args) throws IOException{
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        String[] str=br.readLine().split(" ");
        long S=Long.parseLong(str[0]);
        long W=Long.parseLong(str[1]);
        if(W>=S) System.out.println("unsafe");
        else System.out.println("safe");
        } main {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        String[] str=br.readLine().split(" ");
        long S=Long.parseLong(str[0]);
        long W=Long.parseLong(str[1]);
        if(W>=S) System.out.println("unsafe");
        else System.out.println("safe");
        } BufferedReader br=new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) String[] str=br.readLine().split(" "); str br.readLine().split(" ") br.readLine().split br.readLine() br.readLine br " " long S=Long.parseLong(str[0]); S Long.parseLong(str[0]) Long.parseLong Long str[0] str 0 long W=Long.parseLong(str[1]); W Long.parseLong(str[1]) Long.parseLong Long str[1] str 1 if(W>=S) System.out.println("unsafe");
        else System.out.println("safe"); W>=S W S System.out.println("unsafe") System.out.println System.out System System.out "unsafe" System.out.println("safe") System.out.println System.out System System.out "safe" String[] args args public class Main{  
    public static void main(String[] args) throws IOException{
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        String[] str=br.readLine().split(" ");
        long S=Long.parseLong(str[0]);
        long W=Long.parseLong(str[1]);
        if(W>=S) System.out.println("unsafe");
        else System.out.println("safe");
        }
    } public class Main{  
    public static void main(String[] args) throws IOException{
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        String[] str=br.readLine().split(" ");
        long S=Long.parseLong(str[0]);
        long W=Long.parseLong(str[1]);
        if(W>=S) System.out.println("unsafe");
        else System.out.println("safe");
        }
    } Main
import java.io.*;
import java.lang.*;
import java.util.*;
public class Main{  
    public static void main(String[] args) throws IOException{
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        String[] str=br.readLine().split(" ");
        long S=Long.parseLong(str[0]);
        long W=Long.parseLong(str[1]);
        if(W>=S) System.out.println("unsafe");
        else System.out.println("safe");
        }
    }
