Problem:
Score : 300 points

Problem Statement

You are given an integer sequence of length N, a_1,a_2,...,a_N.

For each 1≤i≤N, you have three choices: add 1 to a_i, subtract 1 from a_i or do nothing.

After these operations, you select an integer X and count the number of i such that a_i=X.

Maximize this count by making optimal choices.

Constraints

1≤N≤10^5

0≤a_i<10^5 (1≤i≤N)

a_i is an integer.

Input

The input is given from Standard Input in the following format:

N
a_1 a_2 .. a_N

Output

Print the maximum possible number of i such that a_i=X.

Sample Input 1

7
3 1 4 1 5 9 2

Sample Output 1

4

For example, turn the sequence into 2,2,3,2,6,9,2 and select X=2 to obtain 4, the maximum possible count.

Sample Input 2

10
0 1 2 3 4 5 6 7 8 9

Sample Output 2

3

Sample Input 3

1
99999

Sample Output 3

1

Solution in C++14 (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <stdio.h>
#include <math.h>
//main definations
#define UI unsigned int
#define LLI long long int
#define ULLI unsigned long long int
void read_array(int *a, int n);
void write_array(int *a, int n);
void sort_array(int *a, int n);
//codechef only
#define TC for(UI defined_i=1;defined_i<=t;defined_i++)
using namespace std;

int main(){
	int n;
	cin>>n;
	int arr[n];
	for(int i=0;i<n;i++){
		cin>>arr[i];
	}
	int max, temp, temp2=1, max2=0;
	for(int i=0;i<n;i++){
		max=0;
		for(int j=0;j<n;j++){
		if(arr[i]==arr[j] || arr[i]==arr[j]-1 || arr[i]==arr[j]+1)
			max++;
		}
		if(max>max2){
			max2=max;
		}
		
	}
	//if(max>=max2 && max>=temp){
		cout<<max2<<endl;
	/* }
	else if(max2>=max && max2>=temp){
		cout<<max2<<endl;
	}
	else{
		cout<<temp<<endl;
	} */
	return 0;
}

void read_array(int *a, int n){
	for(int i=0;i<n;i++){
		cin>>*(a+i);
	}
}
void write_array(int *a, int n){
	for(int i=0;i<n;i++){
		cout<<*(a+i)<<" ";
	}
}
void sort_array(int *a, int n){
	sort(a,a+n);
}