#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll,ll> P;
#define REP(i,n) for(ll i=0;i<ll(n);i++)









const ll MOD=998244353;




int main(){
	cin.tie(nullptr);  ios_base::sync_with_stdio(false);
    ll i,j;





    ll N;
    string A;
    cin >> N >> A;


    if(N==1){
    	cout << 1 << endl;
    	return 0;
    }

    string x="1";
    x+=A;
    x+="0";

    vector<ll> v;
    REP(i,N+1){
    	if(x[i]=='1' && x[i+1]=='0') v.push_back(i);
    }

    ll n=v.size();
    if(n==1){
        cout << 1 << endl;
    	return 0;
    }

    ll ans=1;
    for(i=1;i<n;i++){
    	ll d=v[i]-v[i-1]+1;
    	ans*=d;
    	ans%=MOD;
    }



    cout << ans << endl;







  return 0;

}