#include <iostream>
#include <chrono>
#include <ctime>
#include <thread>

#define n 625000000

using namespace std;


long double sum = 0;
void summa(/*long long &n*/) {
    for (long long i = 1; i < n; i++) {

        sum += (i&1 == 0 ? 1 : -1)*log(i) / i;
    }
}
int main()
{
//  long long n = 62500000000;
    std::chrono::time_point<std::chrono::system_clock> start, end;
    start = std::chrono::system_clock::now();
    summa(/*n*/);
    end = std::chrono::system_clock::now();

    int elapsed_seconds =

std::chrono::duration_cast<std::chrono::milliseconds>
        (end - start).count();
    std::time_t end_time = std::chrono::system_clock::to_time_t(end);
    cout << sum << endl;
    std::cout << "finished computation at " << std::ctime(&end_time)
        << "elapsed time: " << elapsed_seconds << "ms\n";

    return 0;
}

/*
вариант 5
O2/:

x86:
26455 - debug
6987 - release


x64:
20984 - debug
4234 - release



intel compiler release:
x86 - 11305
x64 - 3239


O1/:
x86 - 17543
x64 - 5032


O3/:
x86 - 11253
x64 - 3258

avx:
x86 - 8012
x64 - 3312

parall:
x86 - 2136
x64 - 539


загрузка процессора - 25%
*/