import java.util.Scanner;
class Main{
	private static final int MOD = 998244353;
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[] dp = new int[N];
		dp[2] = 1;
		String S = sc.next();
		for(char c:S.toCharArray()){
			if(c=='L'){
				dp[0] += dp[2];
				if(dp[0]>=MOD)
					dp[0] -= MOD;
				dp[1] = dp[2] = 0;
			}
			if(c=='R'){
				dp[1] += dp[0];
				if(dp[1]>=MOD)
					dp[1] -= MOD;
				dp[1] += dp[2];
				if(dp[1]>=MOD)
					dp[1] -= MOD;
				dp[0] = dp[2] = 0;
			}
			if(c=='U'){
				dp[2] += dp[0];
				if(dp[2]>=MOD)
					dp[2] -= MOD;
				dp[2] += dp[1];
				if(dp[2]>=MOD)
					dp[2] -= MOD;
				dp[0] = dp[1] = 0;
			}
			if(c=='.'){
				int[] next = new int[3];
				next[0] = dp[0]+dp[2];
				if(next[0]>=MOD)
					next[0] -= MOD;
				next[1] = dp[0]+dp[1];
				if(next[1]>=MOD)
					next[1] -= MOD;
				next[1] += dp[2];
				if(next[1]>=MOD)
					next[1] -= MOD;
				next[2] = dp[0]+dp[1];
				if(next[2]>=MOD)
					next[2] -= MOD;
				next[2] += dp[2];
				if(next[2]>=MOD)
					next[2] -= MOD;
				dp = next;
			}
		}
		System.out.println(((dp[0]+dp[1])%MOD+dp[2])%MOD);
	}
}