Baekjoon-14501-퇴사

N = int(input())

T = []
P = []
for _ in range(N):
    t,p = map(int, input().split())
    T.append(t)
    P.append(p)
# DP
dp = [0] * (N+1)
for i in reversed(range(N)):
    if i+T[i] < len(dp):
        dp[i] = max(P[i] + dp[i+T[i]], dp[i+1])
    else:
        dp[i] = dp[i+1]

print(dp[0])