#include <queue>

#include <cstdio>

#include <cstring>

#include <iostream>

#include <algorithm>

#define N 100001

#define LL long long

using namespace std;

int n;

LL ans;

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

struct node

{

	LL d, p;

}a[N];

inline LL read()

{

	LL x = 0, f = 1;

	char ch = getchar();

	for(; !isdigit(ch); ch = getchar()) if(ch == '-') f = -1;

	for(; isdigit(ch); ch = getchar()) x = (x << 1) + (x << 3) + ch - '0';

	return x * f;

} 

inline bool cmp(node x, node y)

{

	return x.d < y.d;

}

int main()

{

	int i, now = 0;

	n = read();

	for(i = 1; i <= n; i++)

		a[i].d = read(), a[i].p = read();

	sort(a + 1, a + n + 1, cmp);

	for(i = 1; i <= n; i++)

		if(q.size() < a[i].d) q.push(a[i].p);

		else if(!q.empty() && a[i].p > q.top())

		{

			q.pop();

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

		}

	while(!q.empty()) ans += q.top(), q.pop();

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

	return 0;

}