import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        
        Scanner scanner = new Scanner(System.in);
        int s = scanner.nextInt();
        int w = scanner.nextInt();
        if(w >= s){System.out.println("unsafe");}
        else{System.out.println("safe");}

        return;
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        
        Scanner scanner = new Scanner(System.in);
        int s = scanner.nextInt();
        int w = scanner.nextInt();
        if(w >= s){System.out.println("unsafe");}
        else{System.out.println("safe");}

        return;
    }
} Main public static void main(String[] args) {
        
        Scanner scanner = new Scanner(System.in);
        int s = scanner.nextInt();
        int w = scanner.nextInt();
        if(w >= s){System.out.println("unsafe");}
        else{System.out.println("safe");}

        return;
    } main {
        
        Scanner scanner = new Scanner(System.in);
        int s = scanner.nextInt();
        int w = scanner.nextInt();
        if(w >= s){System.out.println("unsafe");}
        else{System.out.println("safe");}

        return;
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int s = scanner.nextInt(); s scanner.nextInt() scanner.nextInt scanner int w = scanner.nextInt(); w scanner.nextInt() scanner.nextInt scanner 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" return; String[] args args public class Main {
    public static void main(String[] args) {
        
        Scanner scanner = new Scanner(System.in);
        int s = scanner.nextInt();
        int w = scanner.nextInt();
        if(w >= s){System.out.println("unsafe");}
        else{System.out.println("safe");}

        return;
    }
} public class Main {
    public static void main(String[] args) {
        
        Scanner scanner = new Scanner(System.in);
        int s = scanner.nextInt();
        int w = scanner.nextInt();
        if(w >= s){System.out.println("unsafe");}
        else{System.out.println("safe");}

        return;
    }
} Main
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        
        Scanner scanner = new Scanner(System.in);
        int s = scanner.nextInt();
        int w = scanner.nextInt();
        if(w >= s){System.out.println("unsafe");}
        else{System.out.println("safe");}

        return;
    }
}