N,H=map(int,input().split())
AB=[list(map(int,input().split())) for i in range(N)]
a=max([i[0] for i in AB])
B=sorted([i[1] for i in AB if i[1]>a],reverse=True)
count=0
for b in B:
    H-=b
    count+=1
    if H<=0:
        break
#print(H)
if H>0:
    count+=H//a + 1* (H%a>0)

print(count)
