#include<bits/stdc++.h>
#include<atcoder/all>
#define chmin(x,y) (x) = min((x),(y))
#define chmax(x,y) (x) = max((x),(y))z
using namespace std;
using namespace atcoder;
using ll = long long;
const ll mod = 998244353;
using mint = modint998244353;
using Graph = vector<vector<pair<int,ll>>>;
const vector<int> dx = {1,0,-1,0}, dy = {0,1,0,-1};

double dist(int x1, int y1, int x2, int y2){
  double res = (x1-x2) * (x1-x2) + (y1-y2) * (y1-y2);
  return sqrt(res);
}

ll need(ll n, ll m){
  ll res = 0;
  if(n < 0) return res;
  res = n / m;
  if(n % m > 0) res++;
  return res;
}

ll d2(ll x1, ll y1, ll x2, ll y2){
  // auto [x1,y1] = p;
  // auto [x2,y2] = q;
  ll res = (x1-x2) * (x1-x2) + (y1-y2) * (y1-y2);
  return res;
}

int main(){
  // input + prep
  int N; string S;
  cin >> N >> S;
  
  vector<int> T(N);
  for(int i = 0; i < N; i++){
    if(S[i] == 'L') T[i] = 1;
    if(S[i] == 'R') T[i] = 2;
    if(S[i] == 'U') T[i] = 0;
    if(S[i] == '.') T[i] = -1;
  }
  
  // solve
  vector<vector<mint>> dp(N,vector<mint>(3,0));
  if(T[0] == -1){
    dp[0][0] = 1;
    dp[0][1] = 1;
    dp[0][2] = 1;
  }
  else dp[0][T[0]] = 1;
  
  // cout << T[0];
  
  for(int i = 1; i < N; i++){
    // cout << T[i];
    if(T[i] == -1){
      dp[i][0] = dp[i-1][0] + dp[i-1][1] + dp[i-1][2];
      dp[i][1] = dp[i-1][0] + dp[i-1][1];
      dp[i][2] = dp[i-1][0] + dp[i-1][1] + dp[i-1][2];
    }
    else if(T[i] == 0) dp[i][0] = dp[i-1][0] + dp[i-1][1] + dp[i-1][2];
    else if(T[i] == 1) dp[i][1] = dp[i-1][0] + dp[i-1][1];
    else if(T[i] == 2) dp[i][2] = dp[i-1][0] + dp[i-1][1] + dp[i-1][2];
  }
  // cout << endl;
  
  // output
  mint ans = dp[N-1][0] + dp[N-1][1] + dp[N-1][2];
  cout << ans.val() << endl;
}