
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)

amax=max(A)
B.sort()

if amax>=B[-1]:
    print((H-1+amax)//amax)

cnt=0

for i in  range(N):
    if B[-1-i]>amax:
        H-=B[-1-i]
        cnt+=1
        if H<=0:
            print(cnt)
            exit()

print(cnt+(H-1+amax)//amax)