import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int sheep = sc.nextInt();
        int wolf  = sc.nextInt();
        String ans = "";
      
        if(wolf < sheep){
          ans = "safe";
        }else{
          ans = "unsafe";
        }
        
      	System.out.println(ans);
 
    }
} import java.util.*; util.* java public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int sheep = sc.nextInt();
        int wolf  = sc.nextInt();
        String ans = "";
      
        if(wolf < sheep){
          ans = "safe";
        }else{
          ans = "unsafe";
        }
        
      	System.out.println(ans);
 
    }
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int sheep = sc.nextInt();
        int wolf  = sc.nextInt();
        String ans = "";
      
        if(wolf < sheep){
          ans = "safe";
        }else{
          ans = "unsafe";
        }
        
      	System.out.println(ans);
 
    } main {
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int sheep = sc.nextInt();
        int wolf  = sc.nextInt();
        String ans = "";
      
        if(wolf < sheep){
          ans = "safe";
        }else{
          ans = "unsafe";
        }
        
      	System.out.println(ans);
 
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int sheep = sc.nextInt(); sheep sc.nextInt() sc.nextInt sc int wolf  = sc.nextInt(); wolf sc.nextInt() sc.nextInt sc String ans = ""; ans "" if(wolf < sheep){
          ans = "safe";
        }else{
          ans = "unsafe";
        } wolf < sheep wolf sheep {
          ans = "safe";
        } ans = "safe" ans "safe" {
          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){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int sheep = sc.nextInt();
        int wolf  = sc.nextInt();
        String ans = "";
      
        if(wolf < sheep){
          ans = "safe";
        }else{
          ans = "unsafe";
        }
        
      	System.out.println(ans);
 
    }
} public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int sheep = sc.nextInt();
        int wolf  = sc.nextInt();
        String ans = "";
      
        if(wolf < sheep){
          ans = "safe";
        }else{
          ans = "unsafe";
        }
        
      	System.out.println(ans);
 
    }
} Main
import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int sheep = sc.nextInt();
        int wolf  = sc.nextInt();
        String ans = "";
      
        if(wolf < sheep){
          ans = "safe";
        }else{
          ans = "unsafe";
        }
        
      	System.out.println(ans);
 
    }
}