import sys


def solve():
    input = sys.stdin.readline
    mod = 10 ** 9 + 7
    n, h = list(map(int, input().rstrip('\n').split()))
    ab = [list(map(int, input().rstrip('\n').split())) for _ in range(n)]
    ab.sort(reverse=True)
    ma = ab[0][0]
    ab.sort(key=lambda x: x[1], reverse=True)
    cnt = 0
    for a, b in ab:
        if ma >= b or h <= 0:
            break
        else:
            h -= b
            cnt += 1
    print(cnt + (h + ma - 1) // ma)


if __name__ == '__main__':
    solve()
