import java.util.Scanner;
 
public class Main {
 
	public static final MyScanner in = new MyScanner();

	public static void main(String[] args) {

		int S = in.nextInt();
		int W = in.nextInt();

		System.out.println(W >= S ? "unsafe" : "safe");

	}



	public static class MyScanner {
		Scanner sc = new Scanner(System.in);
		String next() { return sc.next();}
		int nextInt() { return Integer.valueOf(sc.next());}
		long nextLong() { return Long.valueOf(sc.next()); }
	}
} import java.util.Scanner; Scanner java.util public class Main {
 
	public static final MyScanner in = new MyScanner();

	public static void main(String[] args) {

		int S = in.nextInt();
		int W = in.nextInt();

		System.out.println(W >= S ? "unsafe" : "safe");

	}



	public static class MyScanner {
		Scanner sc = new Scanner(System.in);
		String next() { return sc.next();}
		int nextInt() { return Integer.valueOf(sc.next());}
		long nextLong() { return Long.valueOf(sc.next()); }
	}
} Main public static final MyScanner in = new MyScanner(); in new MyScanner() public static void main(String[] args) {

		int S = in.nextInt();
		int W = in.nextInt();

		System.out.println(W >= S ? "unsafe" : "safe");

	} main {

		int S = in.nextInt();
		int W = in.nextInt();

		System.out.println(W >= S ? "unsafe" : "safe");

	} int S = in.nextInt(); S in.nextInt() in.nextInt in int W = in.nextInt(); W in.nextInt() in.nextInt in System.out.println(W >= S ? "unsafe" : "safe") System.out.println System.out System System.out W >= S ? "unsafe" : "safe" W >= S W S "unsafe" "safe" String[] args args public static class MyScanner {
		Scanner sc = new Scanner(System.in);
		String next() { return sc.next();}
		int nextInt() { return Integer.valueOf(sc.next());}
		long nextLong() { return Long.valueOf(sc.next()); }
	} MyScanner Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String next() { return sc.next();} next { return sc.next();} return sc.next(); sc.next() sc.next sc int nextInt() { return Integer.valueOf(sc.next());} nextInt { return Integer.valueOf(sc.next());} return Integer.valueOf(sc.next()); Integer.valueOf(sc.next()) Integer.valueOf Integer sc.next() sc.next sc long nextLong() { return Long.valueOf(sc.next()); } nextLong { return Long.valueOf(sc.next()); } return Long.valueOf(sc.next()); Long.valueOf(sc.next()) Long.valueOf Long sc.next() sc.next sc public class Main {
 
	public static final MyScanner in = new MyScanner();

	public static void main(String[] args) {

		int S = in.nextInt();
		int W = in.nextInt();

		System.out.println(W >= S ? "unsafe" : "safe");

	}



	public static class MyScanner {
		Scanner sc = new Scanner(System.in);
		String next() { return sc.next();}
		int nextInt() { return Integer.valueOf(sc.next());}
		long nextLong() { return Long.valueOf(sc.next()); }
	}
} public class Main {
 
	public static final MyScanner in = new MyScanner();

	public static void main(String[] args) {

		int S = in.nextInt();
		int W = in.nextInt();

		System.out.println(W >= S ? "unsafe" : "safe");

	}



	public static class MyScanner {
		Scanner sc = new Scanner(System.in);
		String next() { return sc.next();}
		int nextInt() { return Integer.valueOf(sc.next());}
		long nextLong() { return Long.valueOf(sc.next()); }
	}
} Main
import java.util.Scanner;
 
public class Main {
 
	public static final MyScanner in = new MyScanner();

	public static void main(String[] args) {

		int S = in.nextInt();
		int W = in.nextInt();

		System.out.println(W >= S ? "unsafe" : "safe");

	}



	public static class MyScanner {
		Scanner sc = new Scanner(System.in);
		String next() { return sc.next();}
		int nextInt() { return Integer.valueOf(sc.next());}
		long nextLong() { return Long.valueOf(sc.next()); }
	}
}