n,h=map(int,input().split())
time=[]
for _ in range(n):
    a,b=map(int,input().split())
    time.append((a,1))
    time.append((b+1,0))
time.sort()
ans=0
cnt=0
for i,j in time:
    if j==1:
        cnt+=1
        ans=max(ans,cnt)
    else:
        cnt-=1
print(ans)