import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		// 入力値の取得
		int S = sc.nextInt();
		int W = sc.nextInt();
		
		// 結果の出力
		System.out.println(S <= W? "unsafe" : "safe");

		sc.close();
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		// 入力値の取得
		int S = sc.nextInt();
		int W = sc.nextInt();
		
		// 結果の出力
		System.out.println(S <= W? "unsafe" : "safe");

		sc.close();
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		// 入力値の取得
		int S = sc.nextInt();
		int W = sc.nextInt();
		
		// 結果の出力
		System.out.println(S <= W? "unsafe" : "safe");

		sc.close();
	} main {
		Scanner sc = new Scanner(System.in);

		// 入力値の取得
		int S = sc.nextInt();
		int W = sc.nextInt();
		
		// 結果の出力
		System.out.println(S <= W? "unsafe" : "safe");

		sc.close();
	} 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 System.out.println(S <= W? "unsafe" : "safe") System.out.println System.out System System.out S <= W? "unsafe" : "safe" S <= W S W "unsafe" "safe" sc.close() sc.close sc String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		// 入力値の取得
		int S = sc.nextInt();
		int W = sc.nextInt();
		
		// 結果の出力
		System.out.println(S <= W? "unsafe" : "safe");

		sc.close();
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		// 入力値の取得
		int S = sc.nextInt();
		int W = sc.nextInt();
		
		// 結果の出力
		System.out.println(S <= W? "unsafe" : "safe");

		sc.close();
	}
} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		// 入力値の取得
		int S = sc.nextInt();
		int W = sc.nextInt();
		
		// 結果の出力
		System.out.println(S <= W? "unsafe" : "safe");

		sc.close();
	}
}
