import sys
import math
from collections import defaultdict
input = sys.stdin.readline
N, H = [int(x) for x in input().strip().split()]
A = [0] * N
B = [0] * N
a_max = 0

for n in range(N):
    a, b = [int(x) for x in input().strip().split()]
    a_max = max(a_max, a)
    A[n] = a
    B[n] = b

if sum(B) >= H:
    ans = 0
    damage = 0
    while damage < H:
        ans += 1
        damage += B[ans-1]
    print(ans)
else:
    B = [b for b in B if b >= a_max]
    ans = len(B)
    ans += math.ceil((H - sum(B)) / a_max)
    print(ans)
