You are going out for a walk, when you suddenly encounter a monster. Fortunately, you have N katana (swords), Katana 1, Katana 2, …, Katana N, and can perform the following two kinds of attacks in any order:    * Wield one of the katana you have. When you wield Katana i (1 ≤ i ≤ N), the monster receives a_i points of damage. The same katana can be wielded any number of times.   * Throw one of the katana you have. When you throw Katana i (1 ≤ i ≤ N) at the monster, it receives b_i points of damage, and you lose the katana. That is, you can no longer wield or throw that katana.  The monster will vanish when the total damage it has received is H points or more. At least how many attacks do you need in order to vanish it in total?


def solve():
    # n, m = map(int, input().split())
    n, m = 4, 1000000000
    swing, throw = [1, 1, 1, 1], [1, 10000000, 99999999, 30000000]
    # swing, throw = [], []
    # for _ in range(n):
    #     a, b = map(int, input().split())
    #     swing.append(a)
    #     throw.append(b)
    swing = sorted(swing)
    throw = sorted(throw)
    max_swing = swing[-1]
    will_throw = [x for x in throw if x > max_swing]

    all_damage = sum(will_throw)
    answer = len(will_throw)
    if all_damage > m:
        for damage in will_throw:
            if all_damage - damage < m:
                print(answer)
            else:
                all_damage -= damage
                answer -= 1
    else:
        print(answer + ((m - all_damage) + (max_swing - 1)) // max_swing)

solve()


def solve():
    n, m = map(int, input().split())
    # n, m = 4, 1000000000
    # swing, throw = [1, 1, 1, 1], [1, 10000000, 99999999, 30000000]
    swing, throw = [], []
    for _ in range(n):
        a, b = map(int, input().split())
        swing.append(a)
        throw.append(b)
    swing = sorted(swing)
    throw = sorted(throw)
    max_swing = swing[-1]
    will_throw = [x for x in throw if x > max_swing]

    all_damage = sum(will_throw)
    answer = len(will_throw)
    if all_damage > m:
        for damage in will_throw:
            if all_damage - damage < m:
                print(answer)
                return
            else:
                all_damage -= damage
                answer -= 1
    else:
        print(answer + ((m - all_damage) + (max_swing - 1)) // max_swing)
        return

solve()