#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

const int mod = 998244353, N = 1e6 + 5;
int fac[N], fac2[N], inv[N];
int qpow(int x, int y)
{
	int ans = 1;
	while(y)
	{
		if(y & 1)
			ans = (ll)ans * x % mod;
		x = (ll)x * x % mod;
		y >>= 1;
	}
	return ans;
}
void prep(int n)
{
	int i;
	fac[0] = 1;
	for(i = 1; i <= n; i++)
		fac[i] = (ll)fac[i - 1] * i % mod;
	inv[n] = qpow(fac[n], mod - 2);
	for(i = n; i >= 1; i--)
		inv[i - 1] = (ll)inv[i] * i % mod;
	fac2[0] = 1;
	for(i = 1; i <= n; i++)
		fac2[i] = (ll)fac2[i - 1] * (i + (mod - 1) / 2) % mod;
}
int calc(int x, int y)
{
	return (ll)fac2[y] * inv[y] % mod * fac2[x - y] % mod * inv[x - y] % mod;
}

int main()
{
	int n, i, ans = 0, x;
	scanf("%d", &n);
	prep(n);
	for(i = 0; i < n; i++)
	{
		scanf("%d", &x);
		if(x)
			ans = (ans + calc(n - 1, i)) % mod;
	}
	ans = (ll)ans * fac[n - 1] % mod * qpow(2, n - 1) % mod;
	printf("%d\n", ans);
	return 0;
}