#include <bits/stdc++.h>

using namespace std;

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


const ll MOD=998244353;
ll dp[2][200010];

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

	ll N;
	string S;
	cin >> N >> S;

	vector<ll> v;
	REP(i,N) if(S[i]=='1') v.push_back(i);

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

	vector<ll> u;
	for(i=1;i<n;i++){
		u.push_back(v[i]-v[i-1]);
	}

	ll m=u.size();
	dp[1][0]=1;
	for(i=1;i<=m;i++){
		dp[0][i]=dp[0][i-1]+dp[1][i-1];
		dp[0][i]%=MOD;
		dp[1][i]=(dp[0][i-1]+dp[1][i-1])*u[i-1];
		dp[1][i]%=MOD;
	}

	cout << (dp[0][m]+dp[1][m])%MOD << endl;




	return 0;
}