N,H = map(int,input().split())
Ma = 1
B = []
for i in range(N):
    a,b = map(int,input().split())
    B.append(b)
    if a > Ma:
        Ma = a
B.sort()
B.reverse()
i = 0
Mb = B[0]
while Mb > Ma:
  i += 1
  if i == N:
    Mb = 0
    B = B[:i]
  else:
    Mb = B[i]
H -= sum(B)
print(i+int(-(-H//Ma)))