import java.util.*;
public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		Scanner cin = new Scanner(System.in);
		
		int S,W;
		
		S = cin.nextInt();
		W = cin.nextInt();
		
		System.out.println(W>=S?"unsafe":"safe");
	}

} import java.util.*; util.* java public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		Scanner cin = new Scanner(System.in);
		
		int S,W;
		
		S = cin.nextInt();
		W = cin.nextInt();
		
		System.out.println(W>=S?"unsafe":"safe");
	}

} Main public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		Scanner cin = new Scanner(System.in);
		
		int S,W;
		
		S = cin.nextInt();
		W = cin.nextInt();
		
		System.out.println(W>=S?"unsafe":"safe");
	} main {
		// TODO Auto-generated method stub
		
		Scanner cin = new Scanner(System.in);
		
		int S,W;
		
		S = cin.nextInt();
		W = cin.nextInt();
		
		System.out.println(W>=S?"unsafe":"safe");
	} Scanner cin = new Scanner(System.in); cin new Scanner(System.in) int S S W; W S = cin.nextInt() S cin.nextInt() cin.nextInt cin W = cin.nextInt() W cin.nextInt() cin.nextInt cin System.out.println(W>=S?"unsafe":"safe") System.out.println System.out System System.out W>=S?"unsafe":"safe" W>=S W S "unsafe" "safe" String[] args args public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		Scanner cin = new Scanner(System.in);
		
		int S,W;
		
		S = cin.nextInt();
		W = cin.nextInt();
		
		System.out.println(W>=S?"unsafe":"safe");
	}

} public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		Scanner cin = new Scanner(System.in);
		
		int S,W;
		
		S = cin.nextInt();
		W = cin.nextInt();
		
		System.out.println(W>=S?"unsafe":"safe");
	}

} Main
import java.util.*;
public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		Scanner cin = new Scanner(System.in);
		
		int S,W;
		
		S = cin.nextInt();
		W = cin.nextInt();
		
		System.out.println(W>=S?"unsafe":"safe");
	}

}
