#define _USE_MATH_DEFINES
#include  <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <string>
#include<math.h>
#include<iomanip>
#include<stdio.h>
#include <stdlib.h>
#include<stdio.h>
#include <queue>
#include<map>
#include <fstream>
#include <sstream>
#include<set>
#include<stack>
#include<time.h>
#include <sys/types.h>
#include <tuple>
#include <numeric>
#include <iterator>

typedef long long int ll;
//#include<bits/stdc++.h>


using namespace std;

ll gcd(ll a, ll b) {
    if (a < b)swap(a, b);
    if (b == 0)return a;
    return gcd(b, a % b);
}
int lcm(int a, int b) {
    return a * b / gcd(a, b);
}




int main()
{

    int Q;
    Q = 1;
    //cin >> Q;   

    while (Q--) {
        int n;
        ll m = 998244353;
        string p;
        cin >> n >> p;
        vector<vector<ll>>r(n + 1, vector<ll>(4));
        r[0][0] = 1;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < 3; j++) {
                if (p[i] == 'U')r[i + 1][0] = (r[i + 1][0] + r[i][j])%m;
                else if(p[i]=='R')r[i + 1][1] = (r[i + 1][1] + r[i][j]) % m;
                else if (p[i] == 'L') {
                    if (j == 1)continue;
                    r[i + 1][2] = (r[i + 1][2] + r[i][j]) % m;
                }
                else {
                    for (int k = 0; k < 3; k++) {
                        if (j == 1 && k == 2)continue;
                        r[i + 1][k] = (r[i + 1][k] + r[i][j]) % m;
                    }
                }

            }
        }
        ll ans = 0;
        for (int i = 0; i < 3; i++) {
            ans += r[n][i];
            ans %= m;
        }
        cout << ans;
    }
        return 0;
}