#include<bits/stdc++.h>
#define mod 998244353
using namespace std;
char s[6000005];
int fi[6000005],cd[6000005];
int lb[6000005][10],dep[6000005];
int cs[6000005];
int main(){
	int n;
	scanf("%d%s",&n,s+1);
	for(int i=n+1;i<=2*n;++i)s[i]=s[i-n];
	fi[0]=-1,cd[0]=-1;
	fi[1]=0,cd[1]=0;
	int tt=1,sl=tt;
	for(int i=1;i<=2*n;++i){
		int wz=sl;
		while(1){
			if(s[i]==s[i-cd[wz]-1])break;
			wz=fi[wz];
		}
		if(!lb[wz][s[i]-'0'])lb[wz][s[i]-'0']=++tt,cd[tt]=cd[wz]+2;
		int cz=lb[wz][s[i]-'0'];
		wz=fi[wz];
		while(~wz){
			if(s[i]==s[i-cd[wz]-1])break;
			wz=fi[wz];
		}
		if(~wz)fi[cz]=lb[wz][s[i]-'0'];
		else fi[cz]=1;
		sl=cz;cs[cz]+=(i>n);
	}
	for(int i=tt;i>=1;--i)cs[fi[i]]+=cs[i];
	int ans=0;
	for(int i=1;i<=tt;++i)if(cd[i]<=n)
		ans=(ans+1ll*cs[i]*cs[i]%mod*cd[i])%mod;
	printf("%d\n",ans);
	return 0;
}