import java.util.Scanner;
import java.util.ArrayList;
import java.util.List;
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("unsafe");			
		}else {
			System.out.println("safe");						
		}
	}
} import java.util.Scanner; Scanner java.util import java.util.ArrayList; ArrayList java.util import java.util.List; List 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("unsafe");			
		}else {
			System.out.println("safe");						
		}
	}
} 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("unsafe");			
		}else {
			System.out.println("safe");						
		}
	} main {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		if(s <= w) {
			System.out.println("unsafe");			
		}else {
			System.out.println("safe");						
		}
	} 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("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 sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		if(s <= w) {
			System.out.println("unsafe");			
		}else {
			System.out.println("safe");						
		}
	}
} 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("unsafe");			
		}else {
			System.out.println("safe");						
		}
	}
} Main
import java.util.Scanner;
import java.util.ArrayList;
import java.util.List;
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("unsafe");			
		}else {
			System.out.println("safe");						
		}
	}
}