#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

// 找到 <= x 的最近可用时间
int findPos(vector<int>& parent, int x) {
    if (x <= 0) return 0;
    if (parent[x] == x) return x;
    return parent[x] = findPos(parent, parent[x]);
}

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

    int n;
    cin >> n;

    vector<pair<int,int>> jobs(n);

    int maxd = 0;
    for (int i = 0; i < n; i++) {
        cin >> jobs[i].first >> jobs[i].second;
        maxd = max(maxd, jobs[i].first);
    }

    // 按收益降序
    sort(jobs.begin(), jobs.end(),
        [](const pair<int,int>& a, const pair<int,int>& b) {
            return a.second > b.second;
        });

    // 并查集初始化
    vector<int> parent(maxd + 1);
    for (int i = 0; i <= maxd; i++) {
        parent[i] = i;
    }

    long long ans = 0;

    for (auto &job : jobs) {
        int d = job.first;
        int p = job.second;

        int pos = findPos(parent, d);

        if (pos > 0) {
            ans += p;
            parent[pos] = findPos(parent, pos - 1);
        }
    }

    cout << ans << "\n";
    return 0;
}