using namespace std;
#include <iostream>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <limits.h>
#include <vector>
#include <map>
#include <bitset>
#include <string>
#include <iterator>
#include <set>
#include <utility>
#include <queue>
#include <numeric>
#include <functional>
#include <ctype.h>
#include <stack>
#include <algorithm>
#include <cstdlib>
#define S(x) scanf("%d",&x)
#define S2(x,y) scanf("%d%d",&x,&y)
#define wl(n) while(n--)
#define ll long long
#define bitcnt(x) __builtin_popcount(x)
#define P(x) printf("%d\n",x)
#define PB push_back
#define MP make_pair
#define fl(i,n) for(i=0;i<n;i++)
#define fil(i,a,n) for(i=a;i<n;i++)
#define rev(i,a,n) for(i=n-1;i>=a;i--)
#define mem(a,i) memset(a,i,sizeof(a))
#define F first
#define S1 second
typedef pair<int,int> P;
vector<int> v1;
pair<int,int> p1;
#define MOD 1000000007
#define debug(x)  printf("####%d####\n",x);
#define nl printf("\n");
#define str string
int a[1234567];
string s;
int dp[1001];
ll pow1(ll x,ll y)
{
    if(y==0)
    return 1;
    ll temp= pow1(x,y/2)%MOD;
    if(y%2==0)
    return (temp*temp)%MOD;
    else
    return (((temp*temp)%MOD)*x)%MOD;
}
bool check(int n,int m)
{
	int i,j,b[101];
	fil(i,n,m+1)
	b[j++]=a[i];
	sort(b,b+j);
	if(abs(b[0]-b[j-1])<=1)
		return true;
	return false;
}
int main()
{
    //std::ios_base::sync_with_stdio(false);
    int t;
    int n,i,j,k,m,l;
    S(n);
    fl(i,n)
    S(a[i]);
    sort(a,a+n);
    int ans=0;
    fl(i,n)
    {
    	fil(j,i,n)
    	{
    		if(check(i,j))
    			ans=max(ans,j-i+1);
    	}
    }
    P(ans);
    return 0;
}