#include using namespace std; int main(void){ long long low=1,hi=1e9,mid=0; while(hi > low+1){ mid = (low + hi)/2; cout << "? " << mid << endl; int res = 0; cin >> res; if(res == 0){ low = mid; }else{ hi = mid; } } cout << "! " << low+1 << endl; return 0; }