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: Wrong Answer)

# include <stdio.h>
int main ()
{
	int a,b,c,p=1,d=1;
	scanf ("%d%d%d",&a,&b,&c);
	int i=0;
     if (a%2!=0||b%2!=0||c%2!=0)
        printf ("%d\n",0);
    else
    {
        for (i=1;i<=10006;++i)
	    {
	     int d=0,e=0,f=0;
	  	 d=a/2;
	  	 e=b/2;
	  	 f=c/2;
	  	 a=e+f;
	  	 b=d+f;
	  	 c=d+e;
	  	 if (a%2!=0||b%2!=0||c%2!=0)
	  	    {
	  	    	p=0;
	  	    	break;
		    }
	    }
	  if (p==0)
	  printf ("%d\n",i);
	else
	  printf ("%d\n",-1);	
	}
    	  
}