#define _USE_MATH_DEFINES
#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define MT make_tuple
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
#define RT return
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vll = vector<ll>;

template<class S, class T>
void psort(vector<S> &u, vector<T> &v, bool isGreater = false) {
    int n = (int)u.size();
    vector<pair<S, T>> vecP(n);
    for (int i = 0; i < n; ++i) {
        vecP[i].first = u[i];
        vecP[i].second = v[i];
    }
    if (isGreater) {
        sort(vecP.rbegin(), vecP.rend());
    } else {
        sort(vecP.begin(), vecP.end());
    }
    for (int i = 0; i < n; ++i) {
        u[i] = vecP[i].first;
        v[i] = vecP[i].second;
    }
}

void solve() {

    int N;
    cin >> N;
    const int M = N / 3;
    const ll INF = LLONG_MAX / 10;
    vll cu(M + 1, INF), ne(M + 1, INF);
    cu[0] = 0;
    vll A(N), B(N);
    rep(i, N) {
        cin >> A[i] >> B[i];
    }

    psort(B, A, true);

    rep(i, N) {
        fill(all(ne), INF);
        for (int j = 0; j < min(i + 1, M + 1); j++) {
            // (i-j)*2日目に買う
            smin(ne[j], cu[j] + A[i]+B[i]*(i-j));
            if (j < M)smin(ne[j + 1], cu[j]);
        }
        swap(cu, ne);
    }

    cout << cu.back() << endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(15);
    solve();
    return 0;
}