import java.util.Scanner;

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

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