import java.util.*;

public class Main {
    
    public static List<Integer> P;
    public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);
        final int S = scanner.nextInt();
        final int W = scanner.nextInt();
        if(S <= W){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
} import java.util.*; util.* java public class Main {
    
    public static List<Integer> P;
    public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);
        final int S = scanner.nextInt();
        final int W = scanner.nextInt();
        if(S <= W){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
} Main public static List<Integer> P; P public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);
        final int S = scanner.nextInt();
        final int W = scanner.nextInt();
        if(S <= W){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    } main {
        Scanner scanner = new Scanner(System.in);
        final int S = scanner.nextInt();
        final int W = scanner.nextInt();
        if(S <= W){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) final int S = scanner.nextInt(); S scanner.nextInt() scanner.nextInt scanner final int W = scanner.nextInt(); W scanner.nextInt() scanner.nextInt scanner if(S <= W){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        } S <= W S W {
            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 class Main {
    
    public static List<Integer> P;
    public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);
        final int S = scanner.nextInt();
        final int W = scanner.nextInt();
        if(S <= W){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
} public class Main {
    
    public static List<Integer> P;
    public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);
        final int S = scanner.nextInt();
        final int W = scanner.nextInt();
        if(S <= W){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
} Main
import java.util.*;

public class Main {
    
    public static List<Integer> P;
    public static void main(String args[]){
        Scanner scanner = new Scanner(System.in);
        final int S = scanner.nextInt();
        final int W = scanner.nextInt();
        if(S <= W){
            System.out.println("unsafe");
        }else{
            System.out.println("safe");
        }

    }
}