MOD=998244353
N=int(input())
S=input()
dp=[0,1,0]
for i in range(N):
	ndp=[(dp[0]+dp[1])%MOD,sum(dp)%MOD,sum(dp)%MOD]
	if S[i]=="L":
		ndp[1]=0
		ndp[2]=0
	if S[i]=="U":
		ndp[0]=0
		ndp[2]=0
	if S[i]=="R":
		ndp[0]=0
		ndp[1]=0
	dp=ndp
print(sum(dp)%MOD)