N,H=list(map(int, input().split()))
ab=[]
amax=0
for i in range(N):
    a,b=list(map(int, input().split()))
    if a>amax:
        amax=a
        ind=i
    ab.append((a,b))

# Sort: O(nlogn)
ab.sort(key=lambda x:x[1], reverse=True)

# Simulation: O(n)
h=0
i=0
cnt=0

while ab[i][1]>amax:
    h+=ab[i][1]
    i+=1
    cnt+=1

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