#include "bits/stdc++.h"
using namespace std;

const long long INF = 1e9;

void solve() {
    long long N, A, B;
    cin >> N;
    vector<pair<long long, long long>> BA(N);
    for (int i = 0; i < N; i++) {
        cin >> A >> B;
        BA.at(i) = make_pair(-B, -A);
    }
    sort(BA.begin(), BA.end());
    long long M = N / 3, t;
    vector<vector<long long>> dp(M + 1, vector<long long>(N + 1, INF));
    //dp.at(i).at(j):i個飛ばしてj-1番目までを選んだときの最小金額
    for (int i = 0; i <= M; i++) dp.at(i).at(i) = 0;
    for (int j = 0; j < N; j++) {
        dp.at(0).at(j + 1) = dp.at(0).at(j) - BA.at(j).second - BA.at(j).first * j;
        //cout << "0 " << j+1 << " " << dp.at(0).at(j+1)<<endl;
        for (int i = 0; i < M; i++) {
            t = dp.at(i + 1).at(j) - BA.at(j).second - BA.at(j).first * (j - i - 1);
            dp.at(i + 1).at(j + 1) = min(t, dp.at(i).at(j));
            //cout << i+1 << " " << j+1 << " " << dp.at(i+1).at(j+1)<<endl;
        }
    }
    cout << dp.at(M).at(N) << endl;
    return;
}

int main() {
    solve();
}