Problem:
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The Maximum Number of Customers

$N$ persons visited a restaurant. The restaurant is open from 0 to $T$. The $i$-th person entered the restaurant at $l_i$ and left at $r_i$. Find the maximum number of persons during the business hours.

Constraints

$ 1 \leq N \leq 10^5 $

$ 1 \leq T \leq 10^5 $

$ 0 \leq l_i < r_i \leq T $

Input

The input is given in the following format.

$N$ $T$

$l_1$ $r_1$

$l_2$ $r_2$

:

$l_N$ $r_N$

Output

Print the maximum number of persons in a line.

Sample Input 1

6 10
0 2
1 3
2 6
3 8
4 10
5 10

Sample Output 1

4

Sample Input 2

2 2
0 1
1 2

Sample Output 2

1

Solution in C++14 (judge verdict: Accepted)

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <string>
#include <sstream>
#include <complex>
#include <vector>
#include <list>
#include <queue>
#include <deque>
#include <stack>
#include <map>
#include <set>
#include <iomanip>
#define rep(i, n) for (int i = 0; i < (int)(n); i++
using namespace std;

int main() {
	int n,t,b,c,to=0,m=0;
	cin>>n>>t;
	vector<int> e(t+1,0),a(t+1,0),l(t+1,0);
	for (int i = 0; i < n;i++) {
		cin>>b>>c;
		a[b]++;
		l[c]++;
	}
	for (int i = 0; i < t; i++) {
		to += a[i] - l[i];
		m = max(m, to);
	}
	cout << m << endl;
}