import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int s,w;
        String ans = "safe";
        
        s = sc.nextInt();
        w = sc.nextInt();
        
        if(s <= w){
            ans = "unsafe";
        }
        
        System.out.println(ans);
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int s,w;
        String ans = "safe";
        
        s = sc.nextInt();
        w = sc.nextInt();
        
        if(s <= w){
            ans = "unsafe";
        }
        
        System.out.println(ans);
    }
} Main public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int s,w;
        String ans = "safe";
        
        s = sc.nextInt();
        w = sc.nextInt();
        
        if(s <= w){
            ans = "unsafe";
        }
        
        System.out.println(ans);
    } main {
        Scanner sc = new Scanner(System.in);
        int s,w;
        String ans = "safe";
        
        s = sc.nextInt();
        w = sc.nextInt();
        
        if(s <= w){
            ans = "unsafe";
        }
        
        System.out.println(ans);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int s s w; w String ans = "safe"; ans "safe" s = sc.nextInt() s sc.nextInt() sc.nextInt sc w = sc.nextInt() w sc.nextInt() sc.nextInt sc if(s <= w){
            ans = "unsafe";
        } s <= w s w {
            ans = "unsafe";
        } ans = "unsafe" ans "unsafe" System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int s,w;
        String ans = "safe";
        
        s = sc.nextInt();
        w = sc.nextInt();
        
        if(s <= w){
            ans = "unsafe";
        }
        
        System.out.println(ans);
    }
} public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int s,w;
        String ans = "safe";
        
        s = sc.nextInt();
        w = sc.nextInt();
        
        if(s <= w){
            ans = "unsafe";
        }
        
        System.out.println(ans);
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int s,w;
        String ans = "safe";
        
        s = sc.nextInt();
        w = sc.nextInt();
        
        if(s <= w){
            ans = "unsafe";
        }
        
        System.out.println(ans);
    }
}
