using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var a = NList;
        WriteLine(Zun(n, a));
    }
    static int Zun(int n, int[] a)
    {
        var r2 = 0;
        var r1 = 1;
        var ans = 0;
        for (var i = 1; i < n; ++i)
        {
            var nr = (a[i - 1] == a[i] ? r1 : r2) + 1;
            ans = Math.Max(ans, nr);
            r2 = r1;
            r1 = nr;
        }
        return ans;
    }
}