#include<bits/stdc++.h>
using ll=long long;
using std::cin;
using std::cout;
using std::endl;
const ll max=1e3;
int main(){
    ll left=0,right=max-1;
    while(left+100<right){
        ll mid=(left+right)/2;
        cout<<"? "<<mid<<endl;
        std::string S,T;
        cin>>S;
        cout<<"? "<<mid+1<<endl;
        cin>>T;
        if(T=="safe") left=mid+1;
        else{
            if(S=="safe") left=mid;
            else right=mid-1;
        }
    }
    ll ans=0;
    for(int i=left;i<=right;i++){
        cout<<"? "<<i<<endl;
        std::string S; cin>>S;
        if(S=="safe"){
            ans=i;
        }
    }
    cout<<"! "<<ans<<endl;
}