import java.util.Scanner;

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

		Scanner scanner = new Scanner(System.in);
		int numOfSheep = scanner.nextInt();
		int numOfWolf = scanner.nextInt();

		if(numOfSheep<=numOfWolf) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}

		scanner.close();
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args ) {

		Scanner scanner = new Scanner(System.in);
		int numOfSheep = scanner.nextInt();
		int numOfWolf = scanner.nextInt();

		if(numOfSheep<=numOfWolf) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}

		scanner.close();
	}
} Main public static void main(String[] args ) {

		Scanner scanner = new Scanner(System.in);
		int numOfSheep = scanner.nextInt();
		int numOfWolf = scanner.nextInt();

		if(numOfSheep<=numOfWolf) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}

		scanner.close();
	} main {

		Scanner scanner = new Scanner(System.in);
		int numOfSheep = scanner.nextInt();
		int numOfWolf = scanner.nextInt();

		if(numOfSheep<=numOfWolf) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}

		scanner.close();
	} Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int numOfSheep = scanner.nextInt(); numOfSheep scanner.nextInt() scanner.nextInt scanner int numOfWolf = scanner.nextInt(); numOfWolf scanner.nextInt() scanner.nextInt scanner if(numOfSheep<=numOfWolf) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		} numOfSheep<=numOfWolf numOfSheep numOfWolf {
			System.out.println("unsafe");
		} System.out.println("unsafe") System.out.println System.out System System.out "unsafe" {
			System.out.println("safe");
		} System.out.println("safe") System.out.println System.out System System.out "safe" scanner.close() scanner.close scanner String[] args args public class Main {
	public static void main(String[] args ) {

		Scanner scanner = new Scanner(System.in);
		int numOfSheep = scanner.nextInt();
		int numOfWolf = scanner.nextInt();

		if(numOfSheep<=numOfWolf) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}

		scanner.close();
	}
} public class Main {
	public static void main(String[] args ) {

		Scanner scanner = new Scanner(System.in);
		int numOfSheep = scanner.nextInt();
		int numOfWolf = scanner.nextInt();

		if(numOfSheep<=numOfWolf) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}

		scanner.close();
	}
} Main
import java.util.Scanner;

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

		Scanner scanner = new Scanner(System.in);
		int numOfSheep = scanner.nextInt();
		int numOfWolf = scanner.nextInt();

		if(numOfSheep<=numOfWolf) {
			System.out.println("unsafe");
		}else {
			System.out.println("safe");
		}

		scanner.close();
	}
}