#include<iostream>
#include<vector>
#include<algorithm>
#include<queue>
using namespace std;
typedef pair<int,int> PII;
const int N = 1e4 + 5;

bool cmp(PII&a, PII&b){
    return a.second < b.second;
}

int main(){
    int n; 
    while(cin >> n){
        priority_queue<int , vector<int>, greater<int>> heap;
        vector<PII> t;
        int res = 0;
        for(int i = 0; i < n; i++){
            int a, b;
            cin >> a >> b;
            t.push_back({a, b});
        }
        sort(t.begin(), t.end(), cmp);
        for(auto p : t){
            int x = p.first, y = p.second;
            heap.push(x);
            if(heap.size() > y) heap.pop();
        }
        while(heap.size()){
            res += heap.top();
            heap.pop();
        }
        cout << res << endl;

    }
    return 0;
}