import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		String result = "unsafe";
		if(s > w)  result = "safe";
		System.out.println(result);

	}

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

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		String result = "unsafe";
		if(s > w)  result = "safe";
		System.out.println(result);

	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		String result = "unsafe";
		if(s > w)  result = "safe";
		System.out.println(result);

	} main {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		String result = "unsafe";
		if(s > w)  result = "safe";
		System.out.println(result);

	} 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 String result = "unsafe"; result "unsafe" if(s > w)  result = "safe"; s > w s w result = "safe" result "safe" System.out.println(result) System.out.println System.out System System.out result String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		String result = "unsafe";
		if(s > w)  result = "safe";
		System.out.println(result);

	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		String result = "unsafe";
		if(s > w)  result = "safe";
		System.out.println(result);

	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int s = sc.nextInt();
		int w = sc.nextInt();
		String result = "unsafe";
		if(s > w)  result = "safe";
		System.out.println(result);

	}

}
