from math import ceil
n,h=map(int,input().split())
A,B=[],[]
for _ in range(n):
    a,b=map(int,input().split())
    A.append(a)
    B.append(b)
a=max(A)
B=sorted(list(filter(lambda x:x>a,B)),reverse=True)
ans=0
i=0
l=len(B)
while h>0 and i<l:
    h-=B[i]
    ans+=1
    i+=1
if h>0:
    ans+=ceil(h/a)
print(ans)