N, H = map(int, input().split())
A, B = [0] * N, [0] * N
for i in range(N):
    A[i], B[i] = map(int, input().split())
amax = max(A)
newb = sorted(b for b in B if b > amax)
cnt = 0
while H > 0 and newb:
    cnt += 1
    H -= newb.pop()
if H > 0:
    cnt += (H + amax - 1) // amax
print(cnt)