import bisect
import math

N, H = map(int, input().split())
ab = [map(int, input().split()) for _ in range(N)]
a, b = [list(i) for i in zip(*ab)]

a.sort()
b.sort()

l = []

for i in range(N):
    if b[i] >= a[-1]:
        l.append(b[i])

print(len(l)+math.ceil((H-sum(l))/a[-1]))