// what is matter? never mind. 
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,sse4,popcnt,abm,mmx,avx,avx2") 
#include<bits/stdc++.h>
#define For(i,a,b) for(int i=(a);i<=(b);++i)
#define Rep(i,a,b) for(int i=(a);i>=(b);--i)
#define ll long long
//#define int long long
#define ull unsigned long long
using namespace std;
inline int read()
{
	char c=getchar();int x=0;bool f=0;
	for(;!isdigit(c);c=getchar())f^=!(c^45);
	for(;isdigit(c);c=getchar())x=(x<<1)+(x<<3)+(c^48);
	if(f)x=-x;return x;
}
 
#define mod 998244353
struct modint{
	int x;
	modint(int o=0){x=o;}
	modint &operator = (int o){return x=o,*this;}
	modint &operator +=(modint o){return x=x+o.x>=mod?x+o.x-mod:x+o.x,*this;}
	modint &operator -=(modint o){return x=x-o.x<0?x-o.x+mod:x-o.x,*this;}
	modint &operator *=(modint o){return x=1ll*x*o.x%mod,*this;}
	modint &operator ^=(int b){
		modint a=*this,c=1;
		for(;b;b>>=1,a*=a)if(b&1)c*=a;
		return x=c.x,*this;
	}
	modint &operator /=(modint o){return *this *=o^=mod-2;}
	friend modint operator +(modint a,modint b){return a+=b;}
	friend modint operator -(modint a,modint b){return a-=b;}
	friend modint operator *(modint a,modint b){return a*=b;}
	friend modint operator /(modint a,modint b){return a/=b;}
	friend modint operator ^(modint a,int b){return a^=b;}
	friend bool operator ==(modint a,int b){return a.x==b;}
	friend bool operator !=(modint a,int b){return a.x!=b;}
	bool operator ! () {return !x;}
	modint operator - () {return x?mod-x:0;}
	bool operator <(const modint&b)const{return x<b.x;}
};
inline modint qpow(modint x,int y){return x^y;}

vector<modint> fac,ifac,iv;
inline void initC(int n)
{
	if(iv.empty())fac=ifac=iv=vector<modint>(2,1);
	int m=iv.size(); ++n;
	if(m>=n)return;
	iv.resize(n),fac.resize(n),ifac.resize(n);
	For(i,m,n-1){
		iv[i]=iv[mod%i]*(mod-mod/i);
		fac[i]=fac[i-1]*i,ifac[i]=ifac[i-1]*iv[i];
	}
}
inline modint C(int n,int m){
	if(m<0||n<m)return 0;
	return initC(n),fac[n]*ifac[m]*ifac[n-m];
}
inline modint sign(int n){return (n&1)?(mod-1):(1);}

#define fi first
#define se second
#define pb push_back
#define mkp make_pair
typedef pair<int,int>pii;
typedef vector<int>vi;

#define maxn 6000005
#define inf 0x3f3f3f3f

int n,m;
char s[maxn];
modint res;

struct PAM{
	int ch[maxn][10],len[maxn],fa[maxn],sz[maxn],lst,cnt;
	modint buc[maxn];
	int getfa(int x,int n){
		while(n-len[x]-1<=0 || s[n-len[x]-1]!=s[n])x=fa[x];
		return x;
	}
	void ins(int c,int n)
	{
		int p=getfa(lst,n);
		if(!ch[p][c]){
			int u=++cnt,t=getfa(fa[p],n);
			len[u]=len[p]+2,fa[u]=ch[t][c],sz[u]=sz[fa[u]]+1;
			ch[p][c]=u;
		}
		lst=ch[p][c];
	}
	void init(){
		len[0]=0,len[1]=-1,fa[0]=1,fa[1]=1,cnt=1;
	}
	vi e[maxn];
	void work(){
		Rep(i,cnt,1){
			buc[fa[i]]+=buc[i];
			if(i>=2 && len[i]<=n) res+=buc[i]*buc[i]*len[i];
		}
	}
}t;

signed main()
{
	n=read();
	scanf("%s",s+1);
	For(i,n+1,n+n)s[i]=s[i-n];
	t.init();
	For(i,1,n+n){
		t.ins(s[i]-'0',i);
		if(i>n) t.buc[t.lst]+=1;
	}
	t.work();
	cout<<res.x;
	return 0;
}
/*

*/