import java.util.*;
import java.io.*;

public class Main {
		public static void main(String[] args) throws IOException {
		
		// 入出力高速化 java.io.* とthrows IOExceptionを忘れずに
		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(S>W? "safe" : "unsafe");
	}
} import java.util.*; util.* java import java.io.*; io.* java public class Main {
		public static void main(String[] args) throws IOException {
		
		// 入出力高速化 java.io.* とthrows IOExceptionを忘れずに
		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(S>W? "safe" : "unsafe");
	}
} Main public static void main(String[] args) throws IOException {
		
		// 入出力高速化 java.io.* とthrows IOExceptionを忘れずに
		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(S>W? "safe" : "unsafe");
	} main {
		
		// 入出力高速化 java.io.* とthrows IOExceptionを忘れずに
		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(S>W? "safe" : "unsafe");
	} BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br 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(S>W? "safe" : "unsafe") System.out.println System.out System System.out S>W? "safe" : "unsafe" S>W S W "safe" "unsafe" String[] args args public class Main {
		public static void main(String[] args) throws IOException {
		
		// 入出力高速化 java.io.* とthrows IOExceptionを忘れずに
		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(S>W? "safe" : "unsafe");
	}
} public class Main {
		public static void main(String[] args) throws IOException {
		
		// 入出力高速化 java.io.* とthrows IOExceptionを忘れずに
		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(S>W? "safe" : "unsafe");
	}
} Main
import java.util.*;
import java.io.*;

public class Main {
		public static void main(String[] args) throws IOException {
		
		// 入出力高速化 java.io.* とthrows IOExceptionを忘れずに
		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(S>W? "safe" : "unsafe");
	}
}
