# -*- coding: utf-8 -*-
from sys import stdin
N, H = [int(x) for x in stdin.readline().rstrip().split()]

a = [0] * N
b = [0] * N

for i in range(N):
    a[i], b[i] = [int(x) for x in stdin.readline().rstrip().split()]

a_max = max(a)
b.sort(reverse=True)

count = 0
j = 0
while(j < len(b)):
    if a_max < b[j] :
        H = H - b[j]
        count = count + 1
        j = j + 1
        if H < 0:
            break

    else:
        break


if H > 0 : 
    count = count + (H // a_max)
    if H % a_max > 0:
        count = count + 1

print(count)


