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()
C = 0
i = 0
while i < len(B) and B[i] > Ma:
  i += 1
H -= sum(B[:i])
print(i+int(-(-H//Ma)))