N, H = map(int, input().split())
a = [0] * N
b = [0] * N
for i in range(N):
    a[i], b[i] = map(int, input().split())

A = int(max(a))
B = [i for i in b if i > A]

B.sort(reverse=True)

Sum = 0

for i in range(len(B)):
    H -= B[i]
    Sum += 1
    if H <= 0:
        break

if H > 0:
    Sum += int((H-1)//A)+1


print(Sum)