#include<bits/stdc++.h>
using namespace std;
using Int=long long;
using Real=long double;
template<class T>inline bool chmin(T&A,T B){return(A>B?A=B,1:0);}
template<class T>inline bool chmax(T&A,T B){return(A<B?A=B,1:0);}
#define REP(i,n)for(int i=0;i<(n);++i)
#define REP1(i,n)for(int i=1;i<=(n);++i)
#define ALL(x)begin(x),end(x)
#define drop(x){cout<<x<<'\n';return;}
const int MOD=998244353;
int N;
string S;
Int dp[2<<17];
void sol()
{
	cin>>N>>S;
	dp[0]=1;
	Int x=1;
	int j=0,cnt=0;
	REP(i,N)
	{
		cnt+=S[i]=='1';
		while(j<N&&cnt&&!(cnt==1&&S[j]=='1'))
		{
			x+=dp[j+1];
			x%=MOD;
			cnt-=S[j]=='1';
			++j;
		}
		if(cnt)dp[i+1]=x;
	}
	cout<<dp[N]<<endl;
}
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	cout<<fixed<<setprecision(16);
	int T=1;
	//cin>>T;
	while(T--)sol();
}