#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 100000000000000000


int main(){
	
	int N;
	cin>>N;
	
	vector<int> a(N);
	rep(i,N){
		cin>>a[i];
	}
	
	map<int,mint> dp;
	dp[1] = 1;
	
	mint ans = 0;
	
	rep(i,N){
		map<int,mint> ndp;
		for(auto x:dp){
			int t = x.first * a[i];
			if(t<=-3||t>=3)t = 3;
			ndp[t] += x.second;
		}
		if(i!=0)ndp[a[i]] += mint(2).pow(i-1);
		ans += ndp[-2] * mint(2).pow(max(0,(N-2)-i));
		
		swap(dp,ndp);
		//cout<<ans.val()<<endl;
	}
	
	rep(i,N-1)ans /= 2;
	
	cout<<ans.val()<<endl;
	
	return 0;
}