백준 14501 퇴사

N = int(input())
T = [0]
P = [0]
D = [0] * (N+2)     #D[0]~D[8]까지
for i in range(N):
    a, b = map(int, input().split(" "))
    T.append(a)
    P.append(b)
for i in range(2, N+2):
    for j in range(1, i):
        D[i] = max(D[i], D[j])
        if i == j + T[j]:
            D[i] = max(D[i], D[j] + P[j])
print(max(D))