import bisect
import math
n,h = map(int,input().split())
a,b = [0]*n,[0]*n
for i in range(n):
	a[i],b[i] = map(int,input().split())
a.sort()
b.sort()
 
d = 0
for i in range(n-bisect.bisect_right(b,a[n-1])):
	d += b[n-1-i]
print(math.ceil((h-d)/a[n-1]) + n-bisect.bisect_right(b,a[n-1]))