import java.util.Scanner;
public class Main {
	public static void main(String[] args){

		Scanner sc = new Scanner(System.in);

		int sheep = sc.nextInt();
		int wolves = sc.nextInt();

		if(sheep > wolves){
			System.out.print("safe");
		}else{
			System.out.print("unsafe");
		}

	return;

	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args){

		Scanner sc = new Scanner(System.in);

		int sheep = sc.nextInt();
		int wolves = sc.nextInt();

		if(sheep > wolves){
			System.out.print("safe");
		}else{
			System.out.print("unsafe");
		}

	return;

	}
} Main public static void main(String[] args){

		Scanner sc = new Scanner(System.in);

		int sheep = sc.nextInt();
		int wolves = sc.nextInt();

		if(sheep > wolves){
			System.out.print("safe");
		}else{
			System.out.print("unsafe");
		}

	return;

	} main {

		Scanner sc = new Scanner(System.in);

		int sheep = sc.nextInt();
		int wolves = sc.nextInt();

		if(sheep > wolves){
			System.out.print("safe");
		}else{
			System.out.print("unsafe");
		}

	return;

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int sheep = sc.nextInt(); sheep sc.nextInt() sc.nextInt sc int wolves = sc.nextInt(); wolves sc.nextInt() sc.nextInt sc if(sheep > wolves){
			System.out.print("safe");
		}else{
			System.out.print("unsafe");
		} sheep > wolves sheep wolves {
			System.out.print("safe");
		} System.out.print("safe") System.out.print System.out System System.out "safe" {
			System.out.print("unsafe");
		} System.out.print("unsafe") System.out.print 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 sheep = sc.nextInt();
		int wolves = sc.nextInt();

		if(sheep > wolves){
			System.out.print("safe");
		}else{
			System.out.print("unsafe");
		}

	return;

	}
} public class Main {
	public static void main(String[] args){

		Scanner sc = new Scanner(System.in);

		int sheep = sc.nextInt();
		int wolves = sc.nextInt();

		if(sheep > wolves){
			System.out.print("safe");
		}else{
			System.out.print("unsafe");
		}

	return;

	}
} Main
import java.util.Scanner;
public class Main {
	public static void main(String[] args){

		Scanner sc = new Scanner(System.in);

		int sheep = sc.nextInt();
		int wolves = sc.nextInt();

		if(sheep > wolves){
			System.out.print("safe");
		}else{
			System.out.print("unsafe");
		}

	return;

	}
}
