N = int(input())
S = str(input())
dp = [[0] * 3 for i in range(N)]
MOD = 998244353

if N == 1:
  if S == "L" or S == "U" or S == "R":
    print(1)
  else:
    print(3)
  exit()


if S[0] == "L":
  dp[0][0] = 1
elif S[0] == "U":
  dp[0][1] = 1
elif S[0] == "R":
  dp[0][2] = 1
else:
  dp[0][0] = 1
  dp[0][1] = 1
  dp[0][2] = 1

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

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