#include <queue>

 #include <cstdio>

 #include <iostream>

 #include <algorithm>

 #define LL long long

 const int MAXN = 1e6 + ;

 int n;

 LL tim, ans;

 struct node

 {

     LL x, y;

 }p[MAXN];

 std::priority_queue <LL, std::vector <LL>, std::greater <LL> > q;

 inline LL read()

 {

     LL x = , f = ;

     char ch = getchar();

     for(; !isdigit(ch); ch = getchar()) if(ch == '-') f = -;

     for(; isdigit(ch); ch = getchar()) x = (x << ) + (x << ) + ch - '';

     return x * f;

 }

 inline bool cmp(node x, node y)

 {

     return x.x < y.x;

 }

 int main()

 {

     int i;

     n = read();

     for(i = ; i <= n; i++) p[i].x = read(), p[i].y = read();

     std::sort(p + , p + n + , cmp);

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

     {

         if(tim < p[i].x) tim++, ans += p[i].y, q.push(p[i].y);

         else if(tim == p[i].x && p[i].y > q.top())

         {

             ans += p[i].y - q.top();

             q.pop();

             q.push(p[i].y);

         }

     }

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

     return ;

 }