求助破解密码，悬赏30

#include <iostream>
using namespace std;

int main() {
    int n = 1001;
    long long sum = 1; 
    int num = 1;

    for (int l = 1; l <= (n - 1) / 2; ++l) {
        int step = 2 * l;
        for (int co = 0; co < 4; ++co) {
            num += step;
            sum += num;  
        }
    }

    cout << sum << endl;
    return 0;
}