mina=10**10
def waru(a,b):
  if a%b==0:
    return a//b
  else:
    return (a//b)+1
N,H=map(int,input().split())
A=list()
B=list()
for i in range(N):
  a,b=map(int,input().split())
  A.append(a)
  B.append(b)
sb=sum(B)
for i in range(N):
  S=[k for k in B if k>A[i]]
  n=sum(S)
  if H-n<=0:
    mina=min(mina,len(S))
  else:
    mina=min(mina,waru(H-n,A[i])+len(S))
print(mina)