#include <vector>
#include <string>
#include <algorithm>
#include <iostream>
#include <iomanip>

using namespace std;

int main(int argc, char * argv[])
{
    vector<int> v(36000000);
    int k = 0;
    for(int i = 1;    i <= 6000; ++i)
        for(int j = 6001; j <= 12000; ++j)
            v[k++] = i*j;
    sort(v.begin(),v.end());
    long long s = 0;
    for(int i = 0; i < 36000000; ++i) s += v[i];
    cout << s;
}