def slove():
    import sys
    import heapq
    input = sys.stdin.readline
    n, h = list(map(int, input().rstrip('\n').split()))
    m_k = 0
    t = []
    heapq.heapify(t)
    for i in range(n):
        a, b = list(map(int, input().rstrip('\n').split()))
        m_k = max(m_k, a)
        heapq.heappush(t, -b)
    cnt = 0
    while True:
        if len(t) != 0:
            p = heapq.heappop(t)
            if m_k < -p:
                h += p
                cnt += 1
            else:
                break
        else:
            break
    print((h + m_k - 1) // m_k + cnt)


if __name__ == '__main__':
    slove()
