#include <iostream>

 #include <cstdio>

 #include <cstring>

 #include <cmath>

 #include <algorithm>

 #include <climits>

 #include <vector>

 #include <queue>

 #include <cstdlib>

 #include <string>

 #include <set>

 #include <stack>

 #define LL long long

 #define INF 0x3f3f3f3f

 #define pii pair<int,int>

 using namespace std;

 const int maxn = ;

 pii d[maxn];

 int main(){

     int n,u,v;

     priority_queue< pii,vector< pii >,greater< pii > > q;

     while(~scanf("%d",&n)){

         LL ans = ;

         while(!q.empty()) q.pop();

         for(int i = ; i < n; ++i)

             scanf("%d %d",&d[i].first,&d[i].second);

         sort(d,d+n);

         for(int i = ; i < n; ++i){

             if(q.size() < d[i].first){

                 ans += d[i].second;

                 q.push(make_pair(d[i].second,d[i].first));

             }else if(q.size() == d[i].first){

                 if(d[i].second > q.top().first){

                     ans += d[i].second - q.top().first;

                     q.pop();

                     q.push(make_pair(d[i].second,d[i].first));

                 }

             }

         }

         printf("%lld\n",ans);

     }

     return ;

 }