#include<bits/stdc++.h>
#define PB push_back
using namespace std;
int const N=1e6+1;
vector<int>g[N];
priority_queue<int>q;
 
int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int n,a,t,w=0;
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>a>>t;
		g[a].PB(t);
	}
	/*for(int i=n;i>0;i--){
		cout<<i<<"  ";
		for(int j:g[i]) cout<<j<<' ';
		cout<<endl;
	}*/
	for(int i=n;i>0;i--){
		while(g[i].empty()==false){
			t=g[i].back();
			g[i].pop_back();
			q.push(t);
		}
		if(!q.empty()){
			w+=q.top();
			q.pop();
		}
	}
	/*for(int i=n;i>0;i--){
		cout<<i<<"  ";
		for(int j:g[i]) cout<<j<<' ';
		cout<<endl;
	}*/
	cout<<w;
}

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NQozIDIKMSAzCjIgMQoyIDQKMSAx

5
3 2
1 3
2 1
2 4
1 1