from collections import defaultdict,deque
import math
def main():
    n,h=map(int, input().split())
    ab = [list(map(int, input().split())) for i in range(n)]
    tmp = max([int(i[0]) for i in ab])
    bs = [int(i[1]) for i in ab]
    bs.sort(reverse = True)
    i = 0
    while(bs[i] > tmp):
        h-=bs[i]
        i+=1
        if(h<=0 or i==n):
            break

    print(i+math.ceil(h/tmp))





if __name__ == '__main__':
    main()
