#include<bits/stdc++.h>
using namespace std;
#define ll long long
const ll mod=998244353;
int n;
char s[6000005];
int ch[6000005][10],fail[6000005],len[6000005],tot=1;
int num[6000005];
int getfail(int x,int i){
	while(i-len[x]-1<=0||s[i-len[x]-1]!=s[i])x=fail[x];
	return x;
}
int main(){
	scanf("%d",&n);
	scanf("%s",s+1);
	for(int i=1;i<=n;i++)s[i+n]=s[i];
	len[1]=-1,fail[0]=1;int now=0;
	for(int i=1;i<=2*n;i++){
		now=getfail(now,i);
		if(!ch[now][s[i]-'0']){
			fail[++tot]=ch[getfail(fail[now],i)][s[i]-'0'];
			ch[now][s[i]-'0']=tot;
			len[tot]=len[now]+2;
		}
		now=ch[now][s[i]-'0'];
		if(i>n)num[now]++;
	}
	for(int i=tot;i>=2;i--)num[fail[i]]+=num[i];
	ll ans=0;
	for(int i=2;i<=tot;i++)if(len[i]<=n)ans=(ans+1ll*len[i]*num[i]%mod*num[i]%mod)%mod;
	printf("%lld\n",ans);
	return 0;
}