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 (GCC 5.4.1) (judge verdict: Runtime Error)

#include<stdio.h>
int main()
{
	int n,a[100000],i,j,flag=0,max;
	int s[100000];
	int s1[100000];
	int s2[100000]; 
	int b[100000]={0};
	scanf("%d",&n);
	for(i=0;i<n;i++)
	scanf("%d",&s[i]);
	for(i=0;i<n;i++)
	s1[i]=s[i]+1; 
	for(i=0;i<n;i++)
	s2[i]=s[i]-1;
	
	
	 int k=0;i=0;
	for(k=0;k<n;k++)
	s[i++]=s[k];
	for(k=0;k<n;k++)
	s[i++]=s1[k];
	for(k=0;k<n;k++)
	s[i++]=s2[k]; 
	

	
	
	for(i=0;i<3*n-1;i++)
	for(j=i+1;j<3*n;j++)
	if(s[i]==s[j])
	b[i]++;
	for(i=0;i<3*n;i++)
	if(b[i]!=0)
	{
		flag=1;
		break;
	}
	if(flag==0)
	{
		printf("1\n");
		return 1; 
	}
	max=b[0];
	for(i=1;i<3*n;i++)
	if(b[i]>max)
	max=b[i];
	for(i=0;i<3*n;i++)
	if(max==b[i])
	{printf("%d\n",b[i]+1);break;} 
	
	
	
}