---

import heapq
n = int(inputC))
tasks = []
for i in range(n):
d, p = map(int, input().split())
tasks. append((d, p))
tasks.sortO)
heap
for d, p in tasks:
heapq.heappushCheap, p)
if lenCheap) > d:
heapq.heappopCheap)
print(sumCheap))