/* -*- coding: utf-8 -*-
 *
 * 2926.cc:  No.2926 Botaoshi - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 200000;
const int MOD = 998244353;

enum { L, R, U };

/* typedef */

/* global variables */

char s[MAX_N + 4];
int dp[MAX_N + 1][3];

/* subroutines */

inline void addmod(int &a, int b) { a = (a + b) % MOD; }

/* main */

int main() {
  int n;
  scanf("%d%s", &n, s);

  dp[0][U] = 1;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < 3; j++)
      if (dp[i][j]) {
	if (s[i] == '.') {
	  for (int j1 = 0; j1 < 3; j1++)
	    if (! (j == R && j1 == L))
	      addmod(dp[i + 1][j1], dp[i][j]);
	}
	else {
	  int j1 = (s[i] == 'L') ? L : (s[i] == 'R') ? R : U;
	  if (! (j == R && j1 == L))
	    addmod(dp[i + 1][j1], dp[i][j]);
	}
      }

  int sum = 0;
  for (int j = 0; j < 3; j++) addmod(sum, dp[n][j]);

  printf("%d\n", sum);
  
  return 0;
}