from collections import defaultdict, Counter, deque
from itertools import groupby, accumulate, combinations, permutations, product, combinations_with_replacement
from bisect import bisect_left, bisect_right
from operator import itemgetter
import math

LMI=lambda:list(map(int, input().split()))
LMS=lambda:list(map(str, input().split()))
MI=lambda:map(int, input().split())
MS=lambda:map(str, input().split())
II=lambda:int(input())
IS=lambda:input().split()
LI=lambda:list(input())


N,H=MI()

T=[0]*(H+1)

for i in range(N):
    a,b=MI()
    T[a]+=1
    T[b+1]-=1
print(max(list(accumulate(T))))