#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#ifdef local
#include <C++/core/io/debug_print.hpp>
#else
#define dump(...) void(0);
#endif

#include <iostream>
#include <ranges>
#include <cassert>
#include <numeric>
namespace man {

}
int main() {
    std::cin.tie(nullptr) -> sync_with_stdio(false);
    using namespace std::views;
    int ok = 1e9, ng = 0, r;
    while(std::abs(ok - ng) > 1) {
    	const auto x = std::midpoint(ok, ng);
    	std::cout << x << std::endl;
    	std::cin >> r;
    	assert(r != -1);
    	if(r == 1) {
    		std::exit(0);
    	}
    	ok = x;
    }
}