N = int(input())

dp = [0] * (N + 1)

for i in range(N):
    next_dp = [0] * (N + 1)
    A, B = map(int, input().split())

    for j in range(N + 1):
        next_dp[j] = dp[j] + A * j
        if j < N:
            next_dp[j] = max(next_dp[j], dp[j + 1] + B)

    dp = next_dp

print(dp[0])