N, H = map(int, input().split())
X = [list(map(int, input().split())) for _ in range(N)]

a, b = zip(*((a, b) for a, b in X))
am = max(a)
b = sorted(b, reverse=True)

ans = 0
h = H
for v in b:
    if v > am:
        h -= v
        ans += 1

    if h <= 0:
        break
        
if h > 0:
    ans += -(-h // am)

print(ans)
