import java.util.Scanner;

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

		Scanner scnr = new Scanner(System.in);
		int numSheep = scnr.nextInt();
		int numWolf = scnr.nextInt();

		if (numSheep > numWolf) {
			System.out.print("safe");
		}
		else if (numSheep < numWolf) {
			System.out.print("unsafe");
		}
		else {
			System.out.print("unsafe");
		}
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {

		Scanner scnr = new Scanner(System.in);
		int numSheep = scnr.nextInt();
		int numWolf = scnr.nextInt();

		if (numSheep > numWolf) {
			System.out.print("safe");
		}
		else if (numSheep < numWolf) {
			System.out.print("unsafe");
		}
		else {
			System.out.print("unsafe");
		}
	}
} Main public static void main(String[] args) {

		Scanner scnr = new Scanner(System.in);
		int numSheep = scnr.nextInt();
		int numWolf = scnr.nextInt();

		if (numSheep > numWolf) {
			System.out.print("safe");
		}
		else if (numSheep < numWolf) {
			System.out.print("unsafe");
		}
		else {
			System.out.print("unsafe");
		}
	} main {

		Scanner scnr = new Scanner(System.in);
		int numSheep = scnr.nextInt();
		int numWolf = scnr.nextInt();

		if (numSheep > numWolf) {
			System.out.print("safe");
		}
		else if (numSheep < numWolf) {
			System.out.print("unsafe");
		}
		else {
			System.out.print("unsafe");
		}
	} Scanner scnr = new Scanner(System.in); scnr new Scanner(System.in) int numSheep = scnr.nextInt(); numSheep scnr.nextInt() scnr.nextInt scnr int numWolf = scnr.nextInt(); numWolf scnr.nextInt() scnr.nextInt scnr if (numSheep > numWolf) {
			System.out.print("safe");
		}
		else if (numSheep < numWolf) {
			System.out.print("unsafe");
		}
		else {
			System.out.print("unsafe");
		} numSheep > numWolf numSheep numWolf {
			System.out.print("safe");
		} System.out.print("safe") System.out.print System.out System System.out "safe" if (numSheep < numWolf) {
			System.out.print("unsafe");
		}
		else {
			System.out.print("unsafe");
		} numSheep < numWolf numSheep numWolf {
			System.out.print("unsafe");
		} System.out.print("unsafe") System.out.print System.out System System.out "unsafe" {
			System.out.print("unsafe");
		} System.out.print("unsafe") System.out.print System.out System System.out "unsafe" String[] args args public class Main {
	public static void main(String[] args) {

		Scanner scnr = new Scanner(System.in);
		int numSheep = scnr.nextInt();
		int numWolf = scnr.nextInt();

		if (numSheep > numWolf) {
			System.out.print("safe");
		}
		else if (numSheep < numWolf) {
			System.out.print("unsafe");
		}
		else {
			System.out.print("unsafe");
		}
	}
} public class Main {
	public static void main(String[] args) {

		Scanner scnr = new Scanner(System.in);
		int numSheep = scnr.nextInt();
		int numWolf = scnr.nextInt();

		if (numSheep > numWolf) {
			System.out.print("safe");
		}
		else if (numSheep < numWolf) {
			System.out.print("unsafe");
		}
		else {
			System.out.print("unsafe");
		}
	}
} Main
import java.util.Scanner;

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

		Scanner scnr = new Scanner(System.in);
		int numSheep = scnr.nextInt();
		int numWolf = scnr.nextInt();

		if (numSheep > numWolf) {
			System.out.print("safe");
		}
		else if (numSheep < numWolf) {
			System.out.print("unsafe");
		}
		else {
			System.out.print("unsafe");
		}
	}
}
