import sys
from math import ceil

def divceil(a,b):
    if a%b > 0:
        return a/b+1
    else:
        return a/b

N, H = [int(x) for x in raw_input().split(" ")]
a, b = [], []
for n in xrange(N):
    _a, _b = [int(x) for x in raw_input().split(" ")]
    a.append(_a)
    b.append(_b)
maxA = max(a)
b = sorted(b, key = lambda x:-x)

damage_sum = 0
for i,_b in enumerate(b):
    if _b > maxA:
        damage_sum += _b
        if damage_sum >= H:
            print i + 1
            sys.exit()
    else:
        i -= 1
        break
print i + 1 + divceil(H-damage_sum, maxA)