import java.util.*;

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

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