import java.io.IOException;
import java.io.PrintStream;
import java.util.Scanner;

public class Main {
	static PrintStream o = System.out;
	
	public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		if (s > w) {
			o.println("safe");
		} else {
			o.println("unsafe");
		}
	}
} import java.io.IOException; IOException java.io import java.io.PrintStream; PrintStream java.io import java.util.Scanner; Scanner java.util public class Main {
	static PrintStream o = System.out;
	
	public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		if (s > w) {
			o.println("safe");
		} else {
			o.println("unsafe");
		}
	}
} Main static PrintStream o = System.out; o System.out System System.out public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		if (s > w) {
			o.println("safe");
		} else {
			o.println("unsafe");
		}
	} main {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		if (s > w) {
			o.println("safe");
		} else {
			o.println("unsafe");
		}
	} 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) {
			o.println("safe");
		} else {
			o.println("unsafe");
		} s > w s w {
			o.println("safe");
		} o.println("safe") o.println o "safe" {
			o.println("unsafe");
		} o.println("unsafe") o.println o "unsafe" String[] args args public class Main {
	static PrintStream o = System.out;
	
	public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		if (s > w) {
			o.println("safe");
		} else {
			o.println("unsafe");
		}
	}
} public class Main {
	static PrintStream o = System.out;
	
	public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		if (s > w) {
			o.println("safe");
		} else {
			o.println("unsafe");
		}
	}
} Main
import java.io.IOException;
import java.io.PrintStream;
import java.util.Scanner;

public class Main {
	static PrintStream o = System.out;
	
	public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		if (s > w) {
			o.println("safe");
		} else {
			o.println("unsafe");
		}
	}
}