n = int(input())
ab = [tuple(map(lambda s_: int(s_), input().split())) for _ in range(n)]
oo = 10**18

# dp_i [j]: あと j 回しばく, max damage
dp = [0] * (n + 1)
for a, b in ab:
    ndp = [-oo] * (n + 1)
    for j in range(n + 1):
        # use a
        ndp[j] = max(ndp[j], dp[j] + a * j)
        if j:
            # use b
            ndp[j - 1] = max(ndp[j - 1], dp[j] + b)
    dp = ndp
print(dp[0])