import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
		String[] st = r.readLine().split(" ");

		int s = Integer.parseInt(st[0]);
		int w = Integer.parseInt(st[1]);

		if (s <= w) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		}

		r.close();
	}
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
		String[] st = r.readLine().split(" ");

		int s = Integer.parseInt(st[0]);
		int w = Integer.parseInt(st[1]);

		if (s <= w) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		}

		r.close();
	}
} Main public static void main(String[] args) throws IOException {
		BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
		String[] st = r.readLine().split(" ");

		int s = Integer.parseInt(st[0]);
		int w = Integer.parseInt(st[1]);

		if (s <= w) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		}

		r.close();
	} main {
		BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
		String[] st = r.readLine().split(" ");

		int s = Integer.parseInt(st[0]);
		int w = Integer.parseInt(st[1]);

		if (s <= w) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		}

		r.close();
	} BufferedReader r = new BufferedReader(new InputStreamReader(System.in)); r new BufferedReader(new InputStreamReader(System.in)) String[] st = r.readLine().split(" "); st r.readLine().split(" ") r.readLine().split r.readLine() r.readLine r " " int s = Integer.parseInt(st[0]); s Integer.parseInt(st[0]) Integer.parseInt Integer st[0] st 0 int w = Integer.parseInt(st[1]); w Integer.parseInt(st[1]) Integer.parseInt Integer st[1] st 1 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" r.close() r.close r String[] args args public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
		String[] st = r.readLine().split(" ");

		int s = Integer.parseInt(st[0]);
		int w = Integer.parseInt(st[1]);

		if (s <= w) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		}

		r.close();
	}
} public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
		String[] st = r.readLine().split(" ");

		int s = Integer.parseInt(st[0]);
		int w = Integer.parseInt(st[1]);

		if (s <= w) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		}

		r.close();
	}
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
		String[] st = r.readLine().split(" ");

		int s = Integer.parseInt(st[0]);
		int w = Integer.parseInt(st[1]);

		if (s <= w) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		}

		r.close();
	}
}