import collections,sys,math,functools,operator,itertools,bisect,heapq,decimal,string,time,random
#sys.setrecursionlimit(10**9)
#sys.set_int_max_str_digits(0)
#input = sys.stdin.readline
n = int(input())
s = input().rstrip()
dp = [[0,0,0] for i in range(n)]
mod = 998244353
if s[0] == 'L':
    dp[0][0] = 1
elif s[0] == 'R':
    dp[0][1]= 1
elif s[0] == 'U':
    dp[0][2] = 1
else:
    dp[0][0] = 1
    dp[0][1] = 1
    dp[0][2] = 1
    
for i in range(1,n):
    for j in range(3):
        if j == 0:
            if s[i] == 'R'or s[i] == 'U':
                continue
        if j == 1:
            if s[i] == 'L'or s[i] == 'U':
                continue
        if j == 2:
            if s[i] == 'R'or s[i] == 'L':
                continue


        for k in range(3):
            if j == 0 and k == 1:
                continue
            dp[i][j] += dp[i-1][k]
            dp[i][j] %= mod
print(sum(dp[-1])%mod)