#include<bits/stdc++.h>
using namespace std;

#define int long long
#define REP(i,m,n) for(int i=(m);i<(n);i++)
#define rep(i,n) REP(i,0,n)
#define pb push_back
#define all(a) a.begin(),a.end()
#define rall(c) (c).rbegin(),(c).rend()
#define mp make_pair
#define endl '\n'
//#define vec vector<ll>
//#define mat vector<vector<ll> >
#define fi first
#define se second
#define double long double
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll> pll;
//typedef long double ld;
typedef complex<double> Complex;
const ll INF=1e9+7;
const ll MOD=998244353;
const ll inf=INF*INF;
const ll mod=MOD;
const ll MAX=200010;
const double PI=acos(-1.0);
typedef vector<vector<ll> > mat;
typedef vector<ll> vec;

//Combination
long long extGCD(long long a,long long mod,long long &x,long long &y){
    if(mod==0){
        x=1;
        y=0;
        return a;
    }
    long long d=extGCD(mod,a%mod,y,x);
    y-=(a/mod)*x;
    return d;
}
long long invmod(long long a,long long mod){
    long long x,y;
    extGCD(a,mod,x,y);
    x%=mod;
    if(x<0)x+=mod;
    return x;
}
ll fac[MAX],finv[MAX],inv[MAX];
void combinit(){
    fac[0]=fac[1]=1;
    finv[0]=finv[1]=1;
    inv[1]=1;
    REP(i,2,MAX){
        fac[i]=fac[i-1]*i%mod;
        inv[i]=invmod(i,mod);
        finv[i]=finv[i-1]*inv[i]%mod;
    }
}
ll comb(ll n,ll k){
    if(n<k)return 0;
    if(n<0||k<0)return 0;
    return fac[n]*(finv[k]*finv[n-k]%mod)%mod;
}
//二分累乗

ll rui(ll a,ll b){
    ll res=1;
    ll x=a;
    while(b){
        if(b&1)res=res*x%mod;
        x=x*x%mod;
        b/=2;
    }
    return res;
}

void solve(){
    combinit();
    ll n;cin>>n;
    vector<ll>a(n);
    vector<ll>b(n);
    rep(i,n)cin>>b[i];
    a[0]=1;
    ll cnta=0,cntb=0;
    REP(i,1,n){
        ll x=n-i,y=i;
        while(x%2==0){
            cnta++;
            x/=2;
        }
        while(y%2==0){
            cntb++;
            y/=2;
        }
        if(cnta>cntb)a[i]=0;
        else a[i]=1;
    }
    ll cnt0=0,cnt1=0;
    ll xo=0;
    rep(i,n){
        if(b[i]==0){
        }else if(b[i]==1){
            if(a[i])xo^=1;
        }else{
            if(a[i]==0)cnt0++;
            else cnt1++;
        }
    }
    ll ans=rui(2,cnt0);
    ll sum=0;
    if(cnt1==0){
        if(xo==0)ans=0;
    }else{
        rep(i,cnt1+1){
            if(i%2==xo)continue;
            sum=(sum+comb(cnt1,i))%mod;
        }
        ans=ans*sum%mod;
    }
    if(ans<0)ans+=mod;
    cout<<ans<<endl;
}

signed main(){
    //cin.tie(0);
    //ios::sync_with_stdio(false);
    solve();
}