import bisect

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()

x = bisect.bisect_left(b, a[-1])
H -= sum(b[x:])

print(N-x+(H+a[-1]-1)//a[-1])