import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		
		StringTokenizer st = new StringTokenizer(br.readLine());
		
		int s = Integer.parseInt(st.nextToken());
		int w = Integer.parseInt(st.nextToken());
		
		if(s > w)
			sb.append("safe\n");
		else
			sb.append("unsafe\n");
		
		System.out.println(sb);
	}

} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.StringTokenizer; StringTokenizer java.util public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		
		StringTokenizer st = new StringTokenizer(br.readLine());
		
		int s = Integer.parseInt(st.nextToken());
		int w = Integer.parseInt(st.nextToken());
		
		if(s > w)
			sb.append("safe\n");
		else
			sb.append("unsafe\n");
		
		System.out.println(sb);
	}

} Main public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		
		StringTokenizer st = new StringTokenizer(br.readLine());
		
		int s = Integer.parseInt(st.nextToken());
		int w = Integer.parseInt(st.nextToken());
		
		if(s > w)
			sb.append("safe\n");
		else
			sb.append("unsafe\n");
		
		System.out.println(sb);
	} main {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		
		StringTokenizer st = new StringTokenizer(br.readLine());
		
		int s = Integer.parseInt(st.nextToken());
		int w = Integer.parseInt(st.nextToken());
		
		if(s > w)
			sb.append("safe\n");
		else
			sb.append("unsafe\n");
		
		System.out.println(sb);
	} BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) StringBuilder sb = new StringBuilder(); sb new StringBuilder() StringTokenizer st = new StringTokenizer(br.readLine()); st new StringTokenizer(br.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(s > w)
			sb.append("safe\n");
		else
			sb.append("unsafe\n"); s > w s w sb.append("safe\n") sb.append sb "safe\n" sb.append("unsafe\n") sb.append sb "unsafe\n" System.out.println(sb) System.out.println System.out System System.out sb String[] args args public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		
		StringTokenizer st = new StringTokenizer(br.readLine());
		
		int s = Integer.parseInt(st.nextToken());
		int w = Integer.parseInt(st.nextToken());
		
		if(s > w)
			sb.append("safe\n");
		else
			sb.append("unsafe\n");
		
		System.out.println(sb);
	}

} public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		
		StringTokenizer st = new StringTokenizer(br.readLine());
		
		int s = Integer.parseInt(st.nextToken());
		int w = Integer.parseInt(st.nextToken());
		
		if(s > w)
			sb.append("safe\n");
		else
			sb.append("unsafe\n");
		
		System.out.println(sb);
	}

} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		
		StringTokenizer st = new StringTokenizer(br.readLine());
		
		int s = Integer.parseInt(st.nextToken());
		int w = Integer.parseInt(st.nextToken());
		
		if(s > w)
			sb.append("safe\n");
		else
			sb.append("unsafe\n");
		
		System.out.println(sb);
	}

}