import sys
import collections


def solve():
    input = sys.stdin.readline
    mod = 10 ** 9 + 7
    n, h = list(map(int, input().rstrip('\n').split()))
    al = []
    bl = []
    for i in range(n):
        a, b = list(map(int, input().rstrip('\n').split()))
        al.append(a)
        bl.append(b)
    al.sort()
    bl.sort()
    al = collections.deque(al)
    bl = collections.deque(bl)
    k = al[-1]
    cnt = 0
    while True:
        if len(bl) != 0:
            p = bl.pop()
            if p > k:
                h -= min(p, h)
                cnt += 1
            else:
                print(cnt + (h + k - 1) // k)
                exit()
        else:
            print(cnt + (h + k - 1) // k)
            exit()


if __name__ == '__main__':
    solve()
