Problem:
MathJax.Hub.Config({ tex2jax: { inlineMath: [["$","$"], ["\\(","\\)"]], processEscapes: true }});

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 Go (judge verdict: Accepted)

package main

import "fmt"

const size = 100001

func main() {
    var n, t int
    var l, r int
    var mem [size]int
    fmt.Scan(&n)
    fmt.Scan(&t)
    for i := 0; i < n; i++ {
        fmt.Scan(&l)
        fmt.Scan(&r)
        mem[l] += 1
        mem[r] -= 1
    }
    ans := mem[0]
    for i := 1; i < t + 1; i++ {
        mem[i] += mem[i - 1]
        if ans < mem[i] {
            ans = mem[i]
        }
    }
    fmt.Println(ans)
}