#include "bits/stdc++.h"

using ll = long long;
using namespace std;

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;

    vector<int> a(n);
    vector<int> b(n);

    for (int i = 0; i < n; i++) {
        cin >> a[i];
        cin >> b[i];
    }

    auto comp_a = [&a](int i, int j) -> bool {
        return pair(a[i], i) < pair(a[j], j);
    };

    auto comp_b = [&b](int i, int j) -> bool {
        return pair(b[i], i) < pair(b[j], j);
    };

    set<int, decltype(comp_a)> Q_a(comp_a);
    set<int, decltype(comp_b)> Q_b(comp_b);

    for (int i = 0; i < n; i++) {
        Q_a.insert(i);
        Q_b.insert(i);
    }

    int cnt = 0;
    ll sum = 0;

    while (cnt != n) {
        if (a[*Q_a.begin()] <= cnt) {
            int i = *Q_a.begin();
            Q_a.erase(i);
            Q_b.erase(i);
        } else {
            int i = *Q_b.begin();
            sum += b[i];
            Q_a.erase(i);
            Q_b.erase(i);
        }

        cnt += 1;
    }

    cout << sum << '\n';
    return 0;
}