#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 4000000000000000001

int main(){
	
	int n;
	cin>>n;
	string s;
	cin>>s;
	
	vector<mint> dp(2,0);
	dp[0] = 1;
	rep(i,n){
		vector<mint> ndp(2,0);
		if(s[i]=='0'){
			ndp = dp;
			ndp[0] += dp[1];
		}
		else{
			ndp[1] = dp[0]+dp[1];
			ndp[1] += dp[1];
		}
		swap(dp,ndp);
	}
	cout<<dp[1].val()<<endl;
	
	return 0;
}