import java.util.*;

public class Main {
	Scanner sc = new Scanner(System.in);
	final int MOD = 998244353;
	final int MAX = Integer.MAX_VALUE;
	final long LMAX = Long.MAX_VALUE;
	int len = 200001;


	void doIt() {
		System.out.println((sc.nextInt()<=sc.nextInt())?"unsafe":"safe");
	}

	public static void main(String[] args) {
		new Main().doIt();
	}
} import java.util.*; util.* java public class Main {
	Scanner sc = new Scanner(System.in);
	final int MOD = 998244353;
	final int MAX = Integer.MAX_VALUE;
	final long LMAX = Long.MAX_VALUE;
	int len = 200001;


	void doIt() {
		System.out.println((sc.nextInt()<=sc.nextInt())?"unsafe":"safe");
	}

	public static void main(String[] args) {
		new Main().doIt();
	}
} Main Scanner sc = new Scanner(System.in); sc new Scanner(System.in) final int MOD = 998244353; MOD 998244353 final int MAX = Integer.MAX_VALUE; MAX Integer.MAX_VALUE Integer Integer.MAX_VALUE final long LMAX = Long.MAX_VALUE; LMAX Long.MAX_VALUE Long Long.MAX_VALUE int len = 200001; len 200001 void doIt() {
		System.out.println((sc.nextInt()<=sc.nextInt())?"unsafe":"safe");
	} doIt {
		System.out.println((sc.nextInt()<=sc.nextInt())?"unsafe":"safe");
	} System.out.println((sc.nextInt()<=sc.nextInt())?"unsafe":"safe") System.out.println System.out System System.out (sc.nextInt()<=sc.nextInt())?"unsafe":"safe" (sc.nextInt()<=sc.nextInt()) sc.nextInt() sc.nextInt sc sc.nextInt() sc.nextInt sc "unsafe" "safe" public static void main(String[] args) {
		new Main().doIt();
	} main {
		new Main().doIt();
	} new Main().doIt() new Main().doIt new Main() String[] args args public class Main {
	Scanner sc = new Scanner(System.in);
	final int MOD = 998244353;
	final int MAX = Integer.MAX_VALUE;
	final long LMAX = Long.MAX_VALUE;
	int len = 200001;


	void doIt() {
		System.out.println((sc.nextInt()<=sc.nextInt())?"unsafe":"safe");
	}

	public static void main(String[] args) {
		new Main().doIt();
	}
} public class Main {
	Scanner sc = new Scanner(System.in);
	final int MOD = 998244353;
	final int MAX = Integer.MAX_VALUE;
	final long LMAX = Long.MAX_VALUE;
	int len = 200001;


	void doIt() {
		System.out.println((sc.nextInt()<=sc.nextInt())?"unsafe":"safe");
	}

	public static void main(String[] args) {
		new Main().doIt();
	}
} Main
import java.util.*;

public class Main {
	Scanner sc = new Scanner(System.in);
	final int MOD = 998244353;
	final int MAX = Integer.MAX_VALUE;
	final long LMAX = Long.MAX_VALUE;
	int len = 200001;


	void doIt() {
		System.out.println((sc.nextInt()<=sc.nextInt())?"unsafe":"safe");
	}

	public static void main(String[] args) {
		new Main().doIt();
	}
}
