#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#include <bits/stdc++.h>
/*
struct Complex { double x, y; };
Complex operator*(Complex lhs, Complex rhs) {
    return Complex{lhs.x * rhs.x - lhs.y * rhs.y, lhs.x * rhs.y + lhs.y * rhs.x};
}
Complex& operator+=(Complex& lhs, Complex rhs) {
    lhs.x += rhs.x;
    lhs.y += rhs.y;
    return lhs;
}
std::ostream& operator<<(std::ostream& os, Complex c) {
    std::cout << "(" << c.x << "," << c.y << ")";
}
*/
using Complex = std::complex<double>;
int main() {
    std::mt19937 gen(123);
    std::uniform_real_distribution<double> dist(-1,1);
    std::vector<Complex> arr(25000);
    for (auto &it : arr) {
        it = Complex{dist(gen), dist(gen)};
    }
    Complex res{0,0};
    for (auto it : arr) {
        for (auto jt : arr) {
            res += it * jt;
        }
    }
    std::cout << res;
    return 0;
}