from math import ceil

N, H = map(int, input().split())

max_A = 0
B = []
for i in range(N):
    a, b = map(int, input().split())
    max_A = max(max_A, a)
    B.append(b)

B.sort()

ans = 0
while B:
    if B[-1] >= max_A:
        H -= B.pop()
        ans += 1
    else:
        break

ans += ceil(H / max_A)
print(ans)
