import bisect
n,h=map(int,input().split())
ab = [list(map(int, input().split())) for _ in range(n)]
a, b = [list(i) for i in zip(*ab)]
b.sort()

k=bisect.bisect_left(b,max(a))
b2=b[k:]
h-=sum(b[k:])
c=len(b2)
c+=(h-1)//max(a)+1

print(c)