import sys
import math
from itertools import product, permutations, combinations, accumulate
from heapq import heapify, heappush, heappop
from collections import deque, defaultdict, Counter
from bisect import bisect, bisect_left, bisect_right
from copy import copy, deepcopy
#from sortedcontainers import SortedSet, SortedList, SortedDict

sys.setrecursionlimit(10**7)
INF = float('inf')
LINF = 1 << 60
MOD = 998244353

def mii():
    return map(int, sys.stdin.readline().split())

N = int(input())
S = input()

# L, R, U
dp = [[0]*3 for _ in range(N)]
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(N-1):
    if S[i+1] == "L":
        dp[i+1][0] = (dp[i][0] + dp[i][2]) % MOD
    elif S[i+1] == "R":
        dp[i+1][1] = sum(dp[i]) % MOD
    elif S[i+1] == "U":
        dp[i+1][2] = sum(dp[i]) % MOD
    else:
        dp[i+1][0] = (dp[i][0] + dp[i][2]) % MOD
        dp[i+1][1] = sum(dp[i]) % MOD
        dp[i+1][2] = sum(dp[i]) % MOD

print(sum(dp[N-1]) % MOD)