#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+1<right){ ll mid=(left+right)/2; cout<<"? "<<mid<<endl; std::string S,T; cin>>S; cout<<"? "<<mid<<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; }