#include <iostream>
#include <queue>
#include <map>
#include <set>
#include <cmath>
#include <cstring>
#include <algorithm>
#include <iomanip>
#include <stack>
#include <numeric>
#include <ctime>
#include <string>
#include <bitset>
#include <unordered_map>
#include <unordered_set>

using namespace std;
using ll = long long;
const ll N = 1e5 + 5, mod = 1e9 + 7, inf = 2e18;
const double esp = 1e-9;

int n;

int a[N];

void solve() {
    cin >> n;

    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    int cont = 1, ans = 0;

    for (int i = 2; i <= n; i++) {
        if (i == n && abs(a[i] - a[i - 1] <= 1))cont++;
        if (abs(a[i] - a[i - 1]) > 1 || i == n) {
            ans = max(ans, cont);
            cont = 1;
        } else {
            cont++;
        }
    }
    cout << ans;
}

int main() {
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    int t = 1;
    // cin >> t;

    while (t--) {
        solve();
    }

    return 0;
}