#include<bits/stdc++.h>
using namespace std;
const int N=1e4+10;
struct node{int x,y;}a[N];
bool cmp(node n1,node n2){ return n1.y<n2.y;}
priority_queue<int,vector<int>,greater<int>>Q,q;
int main()
{
    int n;
    while(scanf("%d",&n)!=EOF)
    {
        for(int i=1;i<=n;i++)scanf("%d%d",&a[i].x,&a[i].y);
        sort(a+1,a+n+1,cmp);
        int ans=0;
        Q=q;
        for(int i=1;i<=n;i++)
        {
            ans+=a[i].x;
            Q.push(a[i].x);
            if(Q.size()>a[i].y)
            {
                ans-=Q.top();Q.pop();
            }
        }
        printf("%d\n",ans);
    }
    return 0;
}