n = int(input())

prev_t = prev_d = None
max_speed = 0
for _ in range(n):
    t, d = map(int, input().split())

    if prev_t is None:
        prev_t = t
        prev_d = d
        continue

    speed = (d - prev_d) / (t - prev_t)
    max_speed = max((speed, max_speed))
    prev_t = t
    prev_d = d

print(int(max_speed))