import sys
import math
N,H=map(int,input().split())
p=[]
x=[list(map(int,input().split())) for i in range(N)]
a=max(x[i][0] for i in range(N))
for i in range(N):
    if x[i][1]>a: p.append(x[i][1])

p.sort(reverse=True)
for i in range(len(p)):
    H-=p[i]
    if H<=0: print(i+1),sys.exit()

print(len(p)+math.ceil(H/a))
    