def main():
    N, H = map(int, input().split())

    A = [0] * N
    B = [0] * N

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

    num = sorted(num_list, reverse=True)

    ans = 0
    for a in num:
        if a in A:
            ans += -(-H // a)
            break
        else:
            ans += 1
            H -= a

    print(ans)

main()