#include<iostream>
using namespace std;
main()
{
	int L=0,R=1000;
	while(R-L>2)
	{
		int M=(L+R)/2;
		string a,b;
		cout<<"? "<<M<<endl;
		cin>>a;
		cout<<"? "<<M+1<<endl;
		cin>>b;
		if(a=="out"&&b=="out")R=M+1;
		else if(a=="out"&&b=="safe")L=M+1;
		else if(a=="safe"&&b=="out")L=M;
		else L=M+1;
	}
	while(true)
	{
		cout<<"? "<<L+1<<endl;
		string a;cin>>a;
		if(a=="out")break;
		L++;
	}
	cout<<"! "<<L<<endl;
}