N=int(input())
S=input()
from collections import deque

dp=[0,1,0]
mod=998244353
for s in S:
  ndp=[0,0,0]
  if s=='U':
    ndp[1]=sum(dp) 
  elif s=='L':
    ndp[2]=dp[1]+dp[2]
  elif s=='R':
    ndp[0]=sum(dp)
  else:
    ndp[0]=sum(dp)
    ndp[1]=sum(dp) 
    ndp[2]=dp[1]+dp[2] 
  dp=[]
  for c in ndp:
    dp.append(c%mod)
    
print(sum(dp)%mod)