import java.util.*;

public class Main {
	static final int r = 1000000000 + 7;

	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt(), w = sc.nextInt();
		String an[] = {"unsafe", "safe"};
		int a = 1;
		if(w >= s)a = 0;
		sc.close();
		System.out.println(an[a]);
	}
} import java.util.*; util.* java public class Main {
	static final int r = 1000000000 + 7;

	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt(), w = sc.nextInt();
		String an[] = {"unsafe", "safe"};
		int a = 1;
		if(w >= s)a = 0;
		sc.close();
		System.out.println(an[a]);
	}
} Main static final int r = 1000000000 + 7; r 1000000000 + 7 1000000000 7 public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt(), w = sc.nextInt();
		String an[] = {"unsafe", "safe"};
		int a = 1;
		if(w >= s)a = 0;
		sc.close();
		System.out.println(an[a]);
	} main {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt(), w = sc.nextInt();
		String an[] = {"unsafe", "safe"};
		int a = 1;
		if(w >= s)a = 0;
		sc.close();
		System.out.println(an[a]);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int s = sc.nextInt() s sc.nextInt() sc.nextInt sc w = sc.nextInt(); w sc.nextInt() sc.nextInt sc String an[] = {"unsafe", "safe"}; an {"unsafe", "safe"} "unsafe" "safe" int a = 1; a 1 if(w >= s)a = 0; w >= s w s a = 0 a 0 sc.close() sc.close sc System.out.println(an[a]) System.out.println System.out System System.out an[a] an a String args[] args public class Main {
	static final int r = 1000000000 + 7;

	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt(), w = sc.nextInt();
		String an[] = {"unsafe", "safe"};
		int a = 1;
		if(w >= s)a = 0;
		sc.close();
		System.out.println(an[a]);
	}
} public class Main {
	static final int r = 1000000000 + 7;

	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt(), w = sc.nextInt();
		String an[] = {"unsafe", "safe"};
		int a = 1;
		if(w >= s)a = 0;
		sc.close();
		System.out.println(an[a]);
	}
} Main
import java.util.*;

public class Main {
	static final int r = 1000000000 + 7;

	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt(), w = sc.nextInt();
		String an[] = {"unsafe", "safe"};
		int a = 1;
		if(w >= s)a = 0;
		sc.close();
		System.out.println(an[a]);
	}
}
