n = int(input())
dp = [[0] * (n + 1) for _ in range(n + 1)]
a = [0] * n
b = [0] * n
for i in range(n):
    a[i], b[i] = map(int, input().split())
a.reverse()
b.reverse()
for i in range(n):
    for j in range(i + 1):
        if dp[i + 1][j] < dp[i][j] + a[i] * j:
            dp[i + 1][j] = dp[i][j] + a[i] * j
        if dp[i + 1][j + 1] < dp[i][j] + b[i]:
            dp[i + 1][j + 1] = dp[i][j] + b[i]
print(max(dp[n]))