import java.io.*;
import java.util.*;

public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(in.readLine());
				
		int S = Integer.parseInt(st.nextToken());
		int W = Integer.parseInt(st.nextToken());
		
		if (W >= S)
			System.out.println("unsafe");
		else
			System.out.println("safe");
	}
} import java.io.*; io.* java import java.util.*; util.* java public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(in.readLine());
				
		int S = Integer.parseInt(st.nextToken());
		int W = Integer.parseInt(st.nextToken());
		
		if (W >= S)
			System.out.println("unsafe");
		else
			System.out.println("safe");
	}
} Main public static void main(String[] args) throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(in.readLine());
				
		int S = Integer.parseInt(st.nextToken());
		int W = Integer.parseInt(st.nextToken());
		
		if (W >= S)
			System.out.println("unsafe");
		else
			System.out.println("safe");
	} main {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(in.readLine());
				
		int S = Integer.parseInt(st.nextToken());
		int W = Integer.parseInt(st.nextToken());
		
		if (W >= S)
			System.out.println("unsafe");
		else
			System.out.println("safe");
	} BufferedReader in = new BufferedReader(new InputStreamReader(System.in)); in new BufferedReader(new InputStreamReader(System.in)) StringTokenizer st = new StringTokenizer(in.readLine()); st new StringTokenizer(in.readLine()) int S = Integer.parseInt(st.nextToken()); S Integer.parseInt(st.nextToken()) Integer.parseInt Integer st.nextToken() st.nextToken st int W = Integer.parseInt(st.nextToken()); W Integer.parseInt(st.nextToken()) Integer.parseInt Integer st.nextToken() st.nextToken st if (W >= S)
			System.out.println("unsafe");
		else
			System.out.println("safe"); W >= S W S System.out.println("unsafe") System.out.println System.out System System.out "unsafe" 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 IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(in.readLine());
				
		int S = Integer.parseInt(st.nextToken());
		int W = Integer.parseInt(st.nextToken());
		
		if (W >= S)
			System.out.println("unsafe");
		else
			System.out.println("safe");
	}
} public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(in.readLine());
				
		int S = Integer.parseInt(st.nextToken());
		int W = Integer.parseInt(st.nextToken());
		
		if (W >= S)
			System.out.println("unsafe");
		else
			System.out.println("safe");
	}
} Main
import java.io.*;
import java.util.*;

public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(in.readLine());
				
		int S = Integer.parseInt(st.nextToken());
		int W = Integer.parseInt(st.nextToken());
		
		if (W >= S)
			System.out.println("unsafe");
		else
			System.out.println("safe");
	}
}
