import java.util.*;
import java.lang.*;

public class Main{

    public static void solve(long s , long w){
        if(w >= s){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }
    }

    public static void gora(){
        Scanner scn = new Scanner(System.in);

        // long test = scn.nextLong();

        long s = scn.nextLong();

        long w = scn.nextLong();

        // long arr[] = new long[n];

        // for(int i = 0 ; i < arr.length ; i++){
        //     arr[i] = scn.nextLong();
        // }

        solve(s, w);
    }

    public static void main(String args[]){
        gora();
    }
}

 import java.util.*; util.* java import java.lang.*; lang.* java public class Main{

    public static void solve(long s , long w){
        if(w >= s){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }
    }

    public static void gora(){
        Scanner scn = new Scanner(System.in);

        // long test = scn.nextLong();

        long s = scn.nextLong();

        long w = scn.nextLong();

        // long arr[] = new long[n];

        // for(int i = 0 ; i < arr.length ; i++){
        //     arr[i] = scn.nextLong();
        // }

        solve(s, w);
    }

    public static void main(String args[]){
        gora();
    }
} Main public static void solve(long s , long w){
        if(w >= s){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }
    } solve {
        if(w >= s){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }
    } 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" long s s long w w public static void gora(){
        Scanner scn = new Scanner(System.in);

        // long test = scn.nextLong();

        long s = scn.nextLong();

        long w = scn.nextLong();

        // long arr[] = new long[n];

        // for(int i = 0 ; i < arr.length ; i++){
        //     arr[i] = scn.nextLong();
        // }

        solve(s, w);
    } gora {
        Scanner scn = new Scanner(System.in);

        // long test = scn.nextLong();

        long s = scn.nextLong();

        long w = scn.nextLong();

        // long arr[] = new long[n];

        // for(int i = 0 ; i < arr.length ; i++){
        //     arr[i] = scn.nextLong();
        // }

        solve(s, w);
    } Scanner scn = new Scanner(System.in); scn new Scanner(System.in) long s = scn.nextLong(); s scn.nextLong() scn.nextLong scn long w = scn.nextLong(); w scn.nextLong() scn.nextLong scn solve(s, w) solve s w public static void main(String args[]){
        gora();
    } main {
        gora();
    } gora() gora String args[] args public class Main{

    public static void solve(long s , long w){
        if(w >= s){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }
    }

    public static void gora(){
        Scanner scn = new Scanner(System.in);

        // long test = scn.nextLong();

        long s = scn.nextLong();

        long w = scn.nextLong();

        // long arr[] = new long[n];

        // for(int i = 0 ; i < arr.length ; i++){
        //     arr[i] = scn.nextLong();
        // }

        solve(s, w);
    }

    public static void main(String args[]){
        gora();
    }
} public class Main{

    public static void solve(long s , long w){
        if(w >= s){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }
    }

    public static void gora(){
        Scanner scn = new Scanner(System.in);

        // long test = scn.nextLong();

        long s = scn.nextLong();

        long w = scn.nextLong();

        // long arr[] = new long[n];

        // for(int i = 0 ; i < arr.length ; i++){
        //     arr[i] = scn.nextLong();
        // }

        solve(s, w);
    }

    public static void main(String args[]){
        gora();
    }
} Main
import java.util.*;
import java.lang.*;

public class Main{

    public static void solve(long s , long w){
        if(w >= s){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }
    }

    public static void gora(){
        Scanner scn = new Scanner(System.in);

        // long test = scn.nextLong();

        long s = scn.nextLong();

        long w = scn.nextLong();

        // long arr[] = new long[n];

        // for(int i = 0 ; i < arr.length ; i++){
        //     arr[i] = scn.nextLong();
        // }

        solve(s, w);
    }

    public static void main(String args[]){
        gora();
    }
}


