import java.util.*;
public class Main{


	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);

		long s  =sc.nextLong();
		long w  =sc.nextLong();
			if(w>=s) {
				System.out.println("unsafe");
			}else {
				System.out.println("safe");

			}
		
	}

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


	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);

		long s  =sc.nextLong();
		long w  =sc.nextLong();
			if(w>=s) {
				System.out.println("unsafe");
			}else {
				System.out.println("safe");

			}
		
	}

} Main public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);

		long s  =sc.nextLong();
		long w  =sc.nextLong();
			if(w>=s) {
				System.out.println("unsafe");
			}else {
				System.out.println("safe");

			}
		
	} main {
		Scanner sc = new Scanner(System.in);

		long s  =sc.nextLong();
		long w  =sc.nextLong();
			if(w>=s) {
				System.out.println("unsafe");
			}else {
				System.out.println("safe");

			}
		
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long s  =sc.nextLong(); s sc.nextLong() sc.nextLong sc long w  =sc.nextLong(); w sc.nextLong() sc.nextLong sc if(w>=s) {
				System.out.println("unsafe");
			}else {
				System.out.println("safe");

			} w>=s w s {
				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" String[] args args public class Main{


	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);

		long s  =sc.nextLong();
		long w  =sc.nextLong();
			if(w>=s) {
				System.out.println("unsafe");
			}else {
				System.out.println("safe");

			}
		
	}

} public class Main{


	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);

		long s  =sc.nextLong();
		long w  =sc.nextLong();
			if(w>=s) {
				System.out.println("unsafe");
			}else {
				System.out.println("safe");

			}
		
	}

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


	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);

		long s  =sc.nextLong();
		long w  =sc.nextLong();
			if(w>=s) {
				System.out.println("unsafe");
			}else {
				System.out.println("safe");

			}
		
	}

}
