import math

N,H=map(int, input().split())

A=[]
B=[]
for i in range(N):
    a,b=map(int, input().split())
    A.append(a)
    B.append(b)

ans=0

B.sort(reverse=True)
Am=max(A)
for i in range(N):
    if B[i]>=Am:
        H-=B[i]
        ans+=1
    if H<=0:
        break

if H>0:
    ans+=math.ceil(H/Am)

print(ans)
