#include<iostream>
#include<thread>
#include<vector>
 
struct Counter {
    volatile int value;
 
    Counter() : value(0){}
 
    void increment(){
        value = value + 1000;
    }
};
 
int main(){
	int n = 10;
	while(n--){
    Counter counter;
 
    std::vector<std::thread> threads;
    for(int i = 0; i < 5; ++i){
        threads.push_back(std::thread([&counter](){
            for(int i = 0; i < 1000000; ++i){
                counter.increment();
            }
        }));
    }
 
    for(auto& thread : threads){
        thread.join();
    }
 
    std::cout << counter.value << std::endl;
	}
    return 0;
}

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