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

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin >> N;
    vector<pair<long long, long long>> BAs(N, pair<long long, long long>());
    for (auto & ba : BAs) cin >> ba.second >> ba.first;
    sort(BAs.begin(), BAs.end());
    reverse(BAs.begin(), BAs.end());
    if (N == 1){
        cout << BAs[0].second << endl;
        return 0;
    }else if (N == 2){
        cout << BAs[0].second + BAs[1].second + BAs[1].first << endl;
        return 0;
    }
    vector<long long> Cs(N, 0);
    long long cum = 0;
    for (int i = N - 1; i >= 0; --i){
        cum += BAs[i].first;
        Cs[i] = cum;
    }
    int K = N / 3;
    vector<vector<long long>> dp(N + 1, vector<long long>(K, 0LL));
    for (int n = 0; n <= N; ++n) for (int k = 0; k <= K; ++k) dp[n][k] = 0LL;
    for (int n = 1; n <= N; ++n){
        for (int k = 1; k <= min(K, n); ++k){
            long long tmp1 = dp[n - 1][k];
            long long tmp2 = dp[n - 1][k - 1] + BAs[n - 1].second + BAs[n - 1].first * (n - 1 - k) + Cs[n - 1];
            dp[n][k] = max(tmp1, tmp2);
        }
    }
    long long ans = 0;
    for (int i = 0; i < N; ++i) ans += BAs[i].first * i + BAs[i].second;
    cout << ans - dp[N][K] << endl;
    return 0;
}