package gioku2020day1;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;

public class F2 {
	static Scanner in;
	static PrintWriter out;
	static String INPUT = "";
	
	static boolean get(int x)
	{
		out.println("? " + x);
		out.flush();
		return in.next().equals("safe");
	}
	
	static void solve()
	{
		int low = 0, high = 1000;
		while(high - low > 1){
			int h = high+low>>1;
			boolean r1 = get(h);
			boolean r2 = get(h+1);
			if(!r1 && !r2){
				high = h;
			}else{
				low = h;
			}
		}
		out.println("! " + (high-1));
		out.flush();
	}

	
	public static void main(String[] args) throws Exception
	{
		in = INPUT.isEmpty() ? new Scanner(System.in) : new Scanner(INPUT);
		out = new PrintWriter(System.out);
		
		solve();
		out.flush();
	}
	
	static int ni() { return Integer.parseInt(in.next()); }
	static long nl() { return Long.parseLong(in.next()); }
	static double nd() { return Double.parseDouble(in.next()); }
	static void tr(Object... o) { if(INPUT.length() != 0)System.out.println(Arrays.deepToString(o)); }
}