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++ (judge verdict: Accepted)

#include <iostream>
#include <algorithm>
using namespace std;

int a[100010];

int main(){
    int N,T,e,q,maxn=0;
    cin>>N>>T;
    for(int i=0;i<N;i++){
        cin>>e>>q;
        a[e]++;
        a[q]--;
    }
    for(int i=1;i<=T+1;i++){
        a[i]+=a[i-1];
        maxn=max(maxn,a[i-1]);
    }
    cout<<maxn<<endl;
    return 0;
}