#include <bits/stdc++.h>
#include <atcoder/all>
#include <boost/polygon/point_data.hpp>
#include <boost/polygon/voronoi.hpp>
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(x) begin(x),end(x)
#define sz(x) (int)(x).size()
using namespace std;
using namespace atcoder;
using ll=long long;
using ld=long double;
using vll=vector<ll>;
using vvll=vector<vll>;
using vi=vector<int>;
using vvi=vector<vi>;
using pll=pair<ll,ll>;
using pi=pair<int,int>;

using mint=modint998244353;

// using BoostPoint=boost::polygon::point_data<int>;
// using Voronoi=boost::polygon::voronoi_diagram<double>;

int main()
{
  	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	ll N;
	string s;
	cin>>N>>s;
	mint total=mint(2).pow(N-1);
	mint ans=0;
	rep(k,0,N){
		vector<mint> dp(N+1),pref(N+1);
		dp[0]=1,pref[0]=1;
		rep(j,1,N+1){
			dp[j]=pref[j-1];
			if(j>k&&s[j-k-1]=='1'){
				dp[j]-=pref[j-k-1];
			}
			pref[j]=pref[j-1]+dp[j];
		}
		mint cnt=total-dp[N];
		ans+=mint(2).pow(k)*cnt;
	}
	cout<<ans.val()<<'\n';

}