import java.util.Scanner;

public class Main {
	public static void main(String[] args){

		int S;
		int W;
		Scanner scan = new Scanner(System.in);

		S = scan.nextInt();
		W = scan.nextInt();

		if(S > W){
			System.out.println("safe");
		}else if(W >= S){
			System.out.println("unsafe");
		}
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args){

		int S;
		int W;
		Scanner scan = new Scanner(System.in);

		S = scan.nextInt();
		W = scan.nextInt();

		if(S > W){
			System.out.println("safe");
		}else if(W >= S){
			System.out.println("unsafe");
		}
	}
} Main public static void main(String[] args){

		int S;
		int W;
		Scanner scan = new Scanner(System.in);

		S = scan.nextInt();
		W = scan.nextInt();

		if(S > W){
			System.out.println("safe");
		}else if(W >= S){
			System.out.println("unsafe");
		}
	} main {

		int S;
		int W;
		Scanner scan = new Scanner(System.in);

		S = scan.nextInt();
		W = scan.nextInt();

		if(S > W){
			System.out.println("safe");
		}else if(W >= S){
			System.out.println("unsafe");
		}
	} int S; S int W; W Scanner scan = new Scanner(System.in); scan new Scanner(System.in) S = scan.nextInt() S scan.nextInt() scan.nextInt scan W = scan.nextInt() W scan.nextInt() scan.nextInt scan if(S > W){
			System.out.println("safe");
		}else if(W >= S){
			System.out.println("unsafe");
		} S > W S W {
			System.out.println("safe");
		} System.out.println("safe") System.out.println System.out System System.out "safe" if(W >= S){
			System.out.println("unsafe");
		} W >= S W S {
			System.out.println("unsafe");
		} System.out.println("unsafe") System.out.println System.out System System.out "unsafe" String[] args args public class Main {
	public static void main(String[] args){

		int S;
		int W;
		Scanner scan = new Scanner(System.in);

		S = scan.nextInt();
		W = scan.nextInt();

		if(S > W){
			System.out.println("safe");
		}else if(W >= S){
			System.out.println("unsafe");
		}
	}
} public class Main {
	public static void main(String[] args){

		int S;
		int W;
		Scanner scan = new Scanner(System.in);

		S = scan.nextInt();
		W = scan.nextInt();

		if(S > W){
			System.out.println("safe");
		}else if(W >= S){
			System.out.println("unsafe");
		}
	}
} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args){

		int S;
		int W;
		Scanner scan = new Scanner(System.in);

		S = scan.nextInt();
		W = scan.nextInt();

		if(S > W){
			System.out.println("safe");
		}else if(W >= S){
			System.out.println("unsafe");
		}
	}
}