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<stdio.h>
#include<stdlib.h>

void run(void){
  int n,t;
  scanf("%d%d",&n,&t);
  int *cnt=(int *)calloc(t+1,sizeof(int));
  while(n--){
    int l,r;
    scanf("%d%d",&l,&r);
    cnt[l]++;
    cnt[r]--;
  }
  int max=cnt[0];
  for(int i=1;i<=t;i++){
    cnt[i]+=cnt[i-1];
    if(cnt[i]>max) max=cnt[i];
  }
  printf("%d\n",max);
}

int main(void){
  run();
  return 0;
}