import math
n,k = map(int,input().split())

lst1 = [list(map(int,input().split())) for i in range(n)]

ans = 0

x = 0
for i in range(n):
    x = max(x,lst1[i][0])

sum1 = 0
for i in range(n):
    if lst1[i][1] > x:
        sum1 += lst1[i][1]
        ans += 1

k -= sum1

print(ans + math.ceil(k/x) )
