#include <iostream>
#include <thread>
#include <mutex>
 
using namespace std;
 
int count = 0;
std::mutex mtx;
 
void foo(){
    for(int i = 0; i < 100000000; i++){
        // std::lock_guard<std::mutex> lock(mtx);
        count++;
    }
}
 
int main(){
    std::thread t1(foo);
    std::thread t2(foo);
    std::thread t3(foo);
    std::thread t4(foo);
 
    t1.join();
    t2.join();
    t3.join();
    t4.join();
 
    cout << count << endl;
 
    return 0;
}

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