import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int s = scan.nextInt();
		int w = scan.nextInt();
		
		if(s <= w) {
			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 scan = new Scanner(System.in);
		int s = scan.nextInt();
		int w = scan.nextInt();
		
		if(s <= w) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}

	}

} Main public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int s = scan.nextInt();
		int w = scan.nextInt();
		
		if(s <= w) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}

	} main {
		Scanner scan = new Scanner(System.in);
		int s = scan.nextInt();
		int w = scan.nextInt();
		
		if(s <= w) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}

	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int s = scan.nextInt(); s scan.nextInt() scan.nextInt scan int w = scan.nextInt(); w scan.nextInt() scan.nextInt scan if(s <= w) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		} s <= w s w {
			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 scan = new Scanner(System.in);
		int s = scan.nextInt();
		int w = scan.nextInt();
		
		if(s <= w) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}

	}

} public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int s = scan.nextInt();
		int w = scan.nextInt();
		
		if(s <= w) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}

	}

} Main
import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int s = scan.nextInt();
		int w = scan.nextInt();
		
		if(s <= w) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}

	}

}
