#include <iostream>
#include <iomanip>
#include <random>
 
using namespace std;
 
mt19937 gen(random_device{}());
uniform_real_distribution<> dis(0.0, 1.0);
 
int howmuch()
{
    int count = 0;
    for(int ok = 0; ok < 2; count++)
        if (dis(gen) < 0.2) ok++;
    return count;
}
 
int main()
{
    int total = 0, ok = 0;
    for(; total < 1000000;)
    {
        ok += howmuch();
        total++;
    }
    cout << double(ok)/total << "\r";
}
 

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