from math import ceil
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)
A.sort()
B.sort()
ans=0
for i in B[::-1]:
    if i<A[-1]:
        break
    H-=i
    ans+=1
    if H<=0:
        print(ans)
        quit()
ans+=ceil(H/A[-1])
print(ans)
