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

struct Counter {
    long long a;
    long long b;
};

void increment(long long& val) {
    for (int i = 0; i < 100'000'000; i++) val++;
}

int main() {
    Counter cnt{ 0, 0 };
    auto start = std::chrono::high_resolution_clock::now();

    std::thread t1(increment, std::ref(cnt.a));
    std::thread t2(increment, std::ref(cnt.b));
    t1.join(); t2.join();

    auto end = std::chrono::high_resolution_clock::now();
    std::cout << "Time: " << std::chrono::duration_cast<std::chrono::milliseconds>(end - start).count() << "ms\n";
    return 0;
}