#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)
#define Inf 1000000001


int main(){
	
	int N;
	cin>>N;
	
	string s = "";
	rep(i,N){
		string t;
		cin>>t;
		s += t;
	}
	
	vector<mint> dp(4,0);
	dp[3] = 1;
	
	rep(i,s.size()){
		vector<mint> ndp(4,0);
		rep(j,4){
			rep(k,4){
				if(k==3)continue;
				if(s[i]=='d'&&k!=1)continue;
				if(s[i]=='k'&&k!=2)continue;
				if(i!=0 && s[i-1]=='.' && s[i]!='.' && j==k)continue;
				if(i%2==0){
					if(i!=0&&k==0&&j!=0)continue;
				}
				else{
					if(j==0&&k!=0)continue;
				}
				ndp[k] += dp[j];
			}
		}
		swap(dp,ndp);
	}
	
	mint ans = 0;
	rep(i,4)ans += dp[i];
	cout<<ans.val()<<endl;
		
	return 0;
}