N,M=map(int,input().split())
ans=[0]*(10**6+1)
for i in range(N):
    a,b=map(int,input().split())
    ans[a]+=1
    ans[b+1]-=1
res=[0]*(10**6+1)
for i in range(M):
    res[i+1]=ans[i]+res[i]
print(max(res))