import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Main {
	
	public static void main(String[] args) throws IOException {
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String line1 = reader.readLine();
		String[] arr1 = line1.split(" ");
		int s = Integer.parseInt(arr1[0]);
		int w = Integer.parseInt(arr1[1]);
		if(w >= s) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		}
	}

} 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 reader = new BufferedReader(new InputStreamReader(System.in));
		String line1 = reader.readLine();
		String[] arr1 = line1.split(" ");
		int s = Integer.parseInt(arr1[0]);
		int w = Integer.parseInt(arr1[1]);
		if(w >= s) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		}
	}

} Main public static void main(String[] args) throws IOException {
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String line1 = reader.readLine();
		String[] arr1 = line1.split(" ");
		int s = Integer.parseInt(arr1[0]);
		int w = Integer.parseInt(arr1[1]);
		if(w >= s) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		}
	} main {
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String line1 = reader.readLine();
		String[] arr1 = line1.split(" ");
		int s = Integer.parseInt(arr1[0]);
		int w = Integer.parseInt(arr1[1]);
		if(w >= s) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		}
	} BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); reader new BufferedReader(new InputStreamReader(System.in)) String line1 = reader.readLine(); line1 reader.readLine() reader.readLine reader String[] arr1 = line1.split(" "); arr1 line1.split(" ") line1.split line1 " " int s = Integer.parseInt(arr1[0]); s Integer.parseInt(arr1[0]) Integer.parseInt Integer arr1[0] arr1 0 int w = Integer.parseInt(arr1[1]); w Integer.parseInt(arr1[1]) Integer.parseInt Integer arr1[1] arr1 1 if(w >= s) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		} w >= s w s {
			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) throws IOException {
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String line1 = reader.readLine();
		String[] arr1 = line1.split(" ");
		int s = Integer.parseInt(arr1[0]);
		int w = Integer.parseInt(arr1[1]);
		if(w >= s) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		}
	}

} public class Main {
	
	public static void main(String[] args) throws IOException {
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String line1 = reader.readLine();
		String[] arr1 = line1.split(" ");
		int s = Integer.parseInt(arr1[0]);
		int w = Integer.parseInt(arr1[1]);
		if(w >= s) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		}
	}

} 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 reader = new BufferedReader(new InputStreamReader(System.in));
		String line1 = reader.readLine();
		String[] arr1 = line1.split(" ");
		int s = Integer.parseInt(arr1[0]);
		int w = Integer.parseInt(arr1[1]);
		if(w >= s) {
			System.out.println("unsafe");
		} else {
			System.out.println("safe");
		}
	}

}
