mod = 998244353

n = int(input())
s = ''.join([input() for i in range(n)])+'.'

notes = ".dk";
dp = [1,0,0]
for i in range(16*n):
    for j in range(3):
        dp[j] %= mod
    nxt = [0]*3
    if s[i] == '.':
        nxt[0] += dp[0]
        if i % 2 == 1:
            nxt[0] += dp[1] + dp[2]
        
        if s[i + 1] != 'd':
            if i % 2 == 0:
                nxt[1] += dp[0]
            nxt[1] += dp[1] + dp[2]
            
        if s[i + 1] != 'k':
            if i % 2 == 0:
                nxt[2] += dp[0]
            nxt[2] += dp[1] + dp[2]
    else:
      if i % 2 == 0:
          nxt[notes.index(s[i])] += dp[0]
      nxt[notes.index(s[i])] += dp[1] + dp[2]
    dp = nxt
print(sum(dp) % mod)