#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <assert.h>
#define IOS ios::sync_with_stdio(false)
using namespace std;
#define inf (0x3f3f3f3f)
typedef long long int LL;


#include <iostream>
#include <sstream>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <string>
const int maxn = 1e3 + 20;
int a[maxn];
void work() {
    int n;
    scanf("%d", &n);
    for (int i = 1; i <= n; ++i) {
        scanf("%d", &a[i]);
    }
    sort(a + 1, a + 1 + n);
    int one = 1, two = 2;
    int ans = 1;
    int mi = a[1];
    int mx = a[2];
    while (two <= n) {
        if (mx - mi > 1) {
            ans = max(ans, two - one);
            one++;
            mi = a[one];
        } else {
            two++;
            mx = a[two];
        }
    }
    two--;
    ans = max(ans, two - one + 1);
    cout << ans << endl;
}

int main() {
#ifdef local
    freopen("data.txt", "r", stdin);
//    freopen("data.txt", "w", stdout);
#endif
    work();
    return 0;
}