#include<bits/stdc++.h>
using namespace std;
struct Assignment {
int deadline, credit;
};
bool compare(const Assignment &a, const Assignment &b) {
return a.deadline < b.deadline;
}
int main() {
int n;
cin >> n;
vector<Assignment> assignments(n);
for(int i = 0; i < n; i++) {
cin >> assignments[i].deadline >> assignments[i].credit;
}
// 按截止日期升序排序
sort(assignments.begin(), assignments.end(), compare);
priority_queue<int, vector<int>, greater<int> > pq;
for (int i = 0; i < n; i++) {
pq.push(assignments[i].credit);
if (pq.size() > assignments[i].deadline) {
pq.pop(); // 移除学分最低的作业
}
}
int totalCredit = 0;
while (!pq.empty()) {
totalCredit += pq.top();
pq.pop();
}
cout << totalCredit << endl;
return 0;
}