//package beg_164;
import java.util.*;
public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		String[] a = s.nextLine().split(" ");
		int b = Integer.parseInt(a[0]);
		int c = Integer.parseInt(a[1]);
		
		if (c>=b) {
			System.out.println("unsafe");
		}
		else {
			System.out.println("safe");
		}
	}

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

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		String[] a = s.nextLine().split(" ");
		int b = Integer.parseInt(a[0]);
		int c = Integer.parseInt(a[1]);
		
		if (c>=b) {
			System.out.println("unsafe");
		}
		else {
			System.out.println("safe");
		}
	}

} Main public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		String[] a = s.nextLine().split(" ");
		int b = Integer.parseInt(a[0]);
		int c = Integer.parseInt(a[1]);
		
		if (c>=b) {
			System.out.println("unsafe");
		}
		else {
			System.out.println("safe");
		}
	} main {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		String[] a = s.nextLine().split(" ");
		int b = Integer.parseInt(a[0]);
		int c = Integer.parseInt(a[1]);
		
		if (c>=b) {
			System.out.println("unsafe");
		}
		else {
			System.out.println("safe");
		}
	} Scanner s = new Scanner(System.in); s new Scanner(System.in) String[] a = s.nextLine().split(" "); a s.nextLine().split(" ") s.nextLine().split s.nextLine() s.nextLine s " " int b = Integer.parseInt(a[0]); b Integer.parseInt(a[0]) Integer.parseInt Integer a[0] a 0 int c = Integer.parseInt(a[1]); c Integer.parseInt(a[1]) Integer.parseInt Integer a[1] a 1 if (c>=b) {
			System.out.println("unsafe");
		}
		else {
			System.out.println("safe");
		} c>=b c b {
			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) {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		String[] a = s.nextLine().split(" ");
		int b = Integer.parseInt(a[0]);
		int c = Integer.parseInt(a[1]);
		
		if (c>=b) {
			System.out.println("unsafe");
		}
		else {
			System.out.println("safe");
		}
	}

} public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		String[] a = s.nextLine().split(" ");
		int b = Integer.parseInt(a[0]);
		int c = Integer.parseInt(a[1]);
		
		if (c>=b) {
			System.out.println("unsafe");
		}
		else {
			System.out.println("safe");
		}
	}

} Main
//package beg_164;
import java.util.*;
public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		String[] a = s.nextLine().split(" ");
		int b = Integer.parseInt(a[0]);
		int c = Integer.parseInt(a[1]);
		
		if (c>=b) {
			System.out.println("unsafe");
		}
		else {
			System.out.println("safe");
		}
	}

}
