#include<iostream>
#include<vector>
#include<algorithm>

using namespace std;
using ll = long long;

#include<atcoder/modint>
using mint = atcoder::modint998244353;

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    int n;
    cin>>n;
    string s;
    cin>>s;
    vector<vector<mint>> dp(n+1,vector<mint>(2,0));
    dp[0][0] = 1;
    for(int i = 0;i<n;i++){
        if(s[i]=='L'||s[i]=='.'){
            dp[i+1][0] += dp[i][0];
        }
        if(s[i]=='U'||s[i]=='.'){
            dp[i+1][0] += dp[i][0];
            dp[i+1][0] += dp[i][1];
        }
        if(s[i]=='R'||s[i]=='.'){
            dp[i+1][1] += dp[i][1] + dp[i][0];
        }
    }
    mint ans = dp[n][0] + dp[n][1];
    cout<<ans.val()<<endl;
}