Baekjoon-15486-퇴사 2

import sys
input = sys.stdin.readline

N = int(input())
T, P = [],[]

for _ in range(N):
    t,p = map(int,input().split())
    T.append(t)
    P.append(p)

dp = [0 for _ in range(N+1)]
for i in range(N-1,-1,-1):
    if i+1 <= N:
        dp[i] = max(dp[i], dp[i+1])
    if i+T[i] <= N:
        dp[i] = max(P[i] + dp[i+T[i]], dp[i])

print(dp[0])