import math
N,H=map(int,input().split())
ab=[[int(x) for x in input().split()] for _ in range(N)]
a,_=max(ab)
B=sorted([b for _,b in ab if b > a], reverse=True)
sb=sum(B)
if sb < H:
	print(len(B)+math.ceil((H-sb)/a))
else:
	B.insert(0, 0)
	for i in range(1, len(B)):
		B[i] += B[i-1]
		if B[i] >= H:
			break
	print(i)
