import java.util.*;

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

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