#include <iostream>

int main(){
    int lb = 10, ub = 1000000001;
    for(int i=0;i<100;i++){
        int mid = (lb + ub) / 2;
        std::cout << "? " << mid << std::endl;
        int res;
        std::cin >> res;
        if(res == 0){
            std::cout << "! " << (mid + i) << std::endl;
            return 0;
        }else if(res == 1){
            lb = mid;
        }else{
            ub = mid;
        }
    }
}