import numpy as np
import functools
import math
import scipy
import fractions
import itertools
 
def solve():
    n, h = map(int, input().split())
    a, b = [0]*n, [0]*n
    for i in range(n):
        a[i],b[i] = map(int, input().split())
    a.sort(reverse = True)
    ans = 0
    m = max(a)
    for i in range(n):
        if b[i] > m:
            h -= b[i]
            ans += 1
        if h <= 0:
            print(ans)
            exit()
    ans += math.ceil(h/m)
    print(ans)
    return 0
 
if __name__ == "__main__":
    solve()
