using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;
class Program
{
    static int NN => int.Parse(ReadLine());
    static long[] NList => ReadLine().Split().Select(long.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var mod = 998_244_353;
        var dp = new long[n + 1][];
        for (var i = 0; i < dp.Length; ++i) dp[i] = new long[n + 1];
        dp[0][0] = 1;
        for (var i = 0; i < n; ++i) for (var j = 0; j < n; ++j)
        {
            dp[i][j + 1] = (dp[i][j + 1] + dp[i][j] * 25) % mod;
            dp[i + 1][j + 1] = (dp[i + 1][j + 1] + dp[i][j]) % mod;
        }
        var ans = 0L;
        for (var i = 3; i <= n; ++i)
        {
            ans = (ans + dp[i][n] * (i / 3)) % mod;
        }
        WriteLine(ans);
    }
}