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

class yuki325
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static string[] SList(int n) => Enumerable.Repeat(0, n).Select(_ => ReadLine()).ToArray();
    static void Main()
    {
        var n = NN;
        var s = string.Concat(SList(n));

        var key = 998244353;
        var dp = new long[s.Length][];
        for (var i = 0; i < dp.Length; ++i) dp[i] = new long[3];

        if (s[0] == 'd') dp[0][1] = 1;
        else if (s[0] == 'k') dp[0][2] = 1;
        else
        {
            dp[0][0] = 1;
            if (s[1] != 'd') dp[0][1] = 1;
            if (s[1] != 'k') dp[0][2] = 1;
        }
        for (var i = 1; i < dp.Length; ++i)
        {
            var prevsum = (dp[i - 1][0] + dp[i - 1][1] + dp[i - 1][2]) % key;
            if (i % 2 == 0)
            {
                if (s[i] == 'd') dp[i][1] = prevsum;
                else if (s[i] == 'k') dp[i][2] = prevsum;
                else
                {
                    dp[i][0] = dp[i - 1][0];
                    if (s[i + 1] != 'd') dp[i][1] = prevsum;
                    if (s[i + 1] != 'k') dp[i][2] = prevsum;
                }
            }
            else
            {
                var prevdk = (dp[i - 1][1] + dp[i - 1][2]) % key;
                if (s[i] == 'd') dp[i][1] = prevdk;
                else if (s[i] == 'k') dp[i][2] = prevdk;
                else
                {
                    dp[i][0] = prevsum;
                    if (i + 1 == s.Length || s[i + 1] != 'd') dp[i][1] = prevdk;
                    if (i + 1 == s.Length || s[i + 1] != 'k') dp[i][2] = prevdk;
                }
            }
        }
        //DebugTable(dp);
        WriteLine(dp[s.Length - 1].Sum() % key);
    }
    static void DebugTable<T>(T[][] table)
    {
        Console.WriteLine("{");
        foreach (var list in table) Console.WriteLine(string.Join(", ", list));
        Console.WriteLine("}");
    }
}