C++ :

#include <iostream>
#include <algorithm>
#include <queue>
#include <vector>
#include <limits.h> 
using namespace std;
const int N=1e4+5;

priority_queue<int,vector<int>,greater<int> > q;
int n;
pair<int,int> p[N];

int main()
{
	while(cin>>n){
		int maxd=INT_MAX;
		for(int i=0;i<n;i++){
			cin>>p[i].second>>p[i].first;
		}
		sort(p,p+n);
		for(int i=0;i<n;i++){
			if(q.size()<p[i].first) q.push(p[i].second);
			else {
				if(p[i].second>q.top()){
					q.pop();
					q.push(p[i].second);
				}
			}
		}
		int ans=0;
		while(!q.empty()){
			ans+=q.top();
			q.pop();
		}
		cout<<ans<<endl;				
	}
	return 0;
}

#include <iostream>
#include <algorithm>
#include <queue>
#include <vector>
#include <limits.h> 
using namespace std;
const int N=1e4+5;

priority_queue<int,vector<int>,greater<int> > q;
int n;
pair<int,int> p[N];

int main()
{
	while(cin>>n){
		int maxd=INT_MAX;
		for(int i=0;i<n;i++){
			cin>>p[i].second>>p[i].first;
		}
		sort(p,p+n);
		for(int i=0;i<n;i++){
			if(q.size()<p[i].first) q.push(p[i].second);
			else {
				if(p[i].second>q.top()){
					q.pop();
					q.push(p[i].second);
				}
			}
		}
		int ans=0;
		while(!q.empty()){
			ans+=q.top();
			q.pop();
		}
		cout<<ans<<endl;				
	}
	return 0;
}