import java.util.Scanner;

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

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