N,H=map(int,input().split())
A=[list(map(int,input().split())) for i in range(N)]
B=[]
C=[]
for a,b in A:
  B.append(a)
  C.append(b)
D=sorted(B)[::-1]
b=D[0]
F=[]
for i in C:
  if b<i:
    F.append(i)
cnt=0
for i in F:
  H-=i
  cnt+=1
  if H<=0:
    print(cnt)
    exit()
print(cnt-((-H)//b))