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

public class Main {
	public static void main(String[] args) throws Exception {
		try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
			String[] sw = br.readLine().split(" ");
			int s = Integer.parseInt(sw[0]);
			int w = Integer.parseInt(sw[1]);
			System.out.println((w >= s) ? "unsafe" : "safe");
		}
	}
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io public class Main {
	public static void main(String[] args) throws Exception {
		try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
			String[] sw = br.readLine().split(" ");
			int s = Integer.parseInt(sw[0]);
			int w = Integer.parseInt(sw[1]);
			System.out.println((w >= s) ? "unsafe" : "safe");
		}
	}
} Main public static void main(String[] args) throws Exception {
		try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
			String[] sw = br.readLine().split(" ");
			int s = Integer.parseInt(sw[0]);
			int w = Integer.parseInt(sw[1]);
			System.out.println((w >= s) ? "unsafe" : "safe");
		}
	} main {
		try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
			String[] sw = br.readLine().split(" ");
			int s = Integer.parseInt(sw[0]);
			int w = Integer.parseInt(sw[1]);
			System.out.println((w >= s) ? "unsafe" : "safe");
		}
	} try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
			String[] sw = br.readLine().split(" ");
			int s = Integer.parseInt(sw[0]);
			int w = Integer.parseInt(sw[1]);
			System.out.println((w >= s) ? "unsafe" : "safe");
		} {
			String[] sw = br.readLine().split(" ");
			int s = Integer.parseInt(sw[0]);
			int w = Integer.parseInt(sw[1]);
			System.out.println((w >= s) ? "unsafe" : "safe");
		} BufferedReader br = new BufferedReader(new InputStreamReader(System.in)) BufferedReader br = new BufferedReader(new InputStreamReader(System.in)) new BufferedReader(new InputStreamReader(System.in)) String[] sw = br.readLine().split(" "); sw br.readLine().split(" ") br.readLine().split br.readLine() br.readLine br " " int s = Integer.parseInt(sw[0]); s Integer.parseInt(sw[0]) Integer.parseInt Integer sw[0] sw 0 int w = Integer.parseInt(sw[1]); w Integer.parseInt(sw[1]) Integer.parseInt Integer sw[1] sw 1 System.out.println((w >= s) ? "unsafe" : "safe") System.out.println System.out System System.out (w >= s) ? "unsafe" : "safe" (w >= s) w s "unsafe" "safe" String[] args args public class Main {
	public static void main(String[] args) throws Exception {
		try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
			String[] sw = br.readLine().split(" ");
			int s = Integer.parseInt(sw[0]);
			int w = Integer.parseInt(sw[1]);
			System.out.println((w >= s) ? "unsafe" : "safe");
		}
	}
} public class Main {
	public static void main(String[] args) throws Exception {
		try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
			String[] sw = br.readLine().split(" ");
			int s = Integer.parseInt(sw[0]);
			int w = Integer.parseInt(sw[1]);
			System.out.println((w >= s) ? "unsafe" : "safe");
		}
	}
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws Exception {
		try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
			String[] sw = br.readLine().split(" ");
			int s = Integer.parseInt(sw[0]);
			int w = Integer.parseInt(sw[1]);
			System.out.println((w >= s) ? "unsafe" : "safe");
		}
	}
}