#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
#define drep(i, cc, n) for (ll i = (cc); i <= (n); ++i)
#define rep(i, n) drep(i, 0, n - 1)
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fi first
#define se second
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
const ll MOD1000000007 = 1000000007;
const ll MOD998244353 = 998244353;
const ll MOD[3] = {999727999, 1070777777, 1000000007};
const ll LINF = 1LL << 60LL;
const int IINF = (1 << 30) - 1;


template<long long mod>
class modint{
    long long x;
public:
    modint(long long x=0) : x((x%mod+mod)%mod) {}
    modint operator-() const { 
      return modint(-x);
    }
    bool operator==(const modint& a){
        if(x == a) return true;
        else return false;
    }
    bool operator==(long long a){
        if(x == a) return true;
        else return false;
    }
    bool operator!=(const modint& a){
        if(x != a) return true;
        else return false;
    }
    bool operator!=(long long a){
        if(x != a) return true;
        else return false;
    }
    modint& operator+=(const modint& a) {
        if ((x += a.x) >= mod) x -= mod;
        return *this;
    }
    modint& operator-=(const modint& a) {
        if ((x += mod-a.x) >= mod) x -= mod;
        return *this;
    }
    modint& operator*=(const  modint& a) {
        (x *= a.x) %= mod;
        return *this;
    }
    modint operator+(const modint& a) const {
        modint res(*this);
        return res+=a;
    }
    modint operator-(const modint& a) const {
        modint res(*this);
        return res-=a;
    }
    modint operator*(const modint& a) const {
        modint res(*this);
        return res*=a;
    }
    modint pow(long long t) const {
        if (!t) return 1;
        modint a = pow(t>>1);
        a *= a;
        if (t&1) a *= *this;
        return a;
    }
    // for prime mod
    modint inv() const {
        return pow(mod-2);
    }
    modint& operator/=(const modint& a) {
        return (*this) *= a.inv();
    }
    modint operator/(const modint& a) const {
        modint res(*this);
        return res/=a;
    }

    friend std::istream& operator>>(std::istream& is, modint& m) noexcept {
        is >> m.x;
        m.x %= mod;
        if (m.x < 0) m.x += mod;
        return is;
    }

    friend ostream& operator<<(ostream& os, const modint& m){
        os << m.x;
        return os;
    }
};

using mint = modint<MOD998244353>;

void solve(){
    ll n; cin >> n;
    string s; cin >> s;

    //全部0の場合
    {
        bool flg = true;
        rep(i, n) if(s[i]=='1') flg = false;

        if(flg){
            cout << 0 << endl;
            return;
        }
    }

    ll l = 0, r = n-1;
    while(s[l]=='0') l++;
    while(s[r]=='0') r--;

    mint ans = 1;
    ll cnt = 1;
    ll sum = r-l;
    for(ll i=l+1; i<=r; i++){
        if(s[i-1]==s[i]){
            cnt++;
        }else{
            if(s[i-1]=='0'){
                ans *= cnt+2;
                sum -= cnt+1;
            }
            cnt = 1;
        }
    }

    ans *= mint(2).pow(sum);
    cout << ans << endl;
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    int T=1;
    //cin >> T;
    while(T--) solve();
}