#include <bits/stdc++.h>

using namespace std;
//#define int long long
const int maxn = 6000000 + 5;
const int mod = 998244353;
int n;

struct pam {
    int sz, tot, last;
    int cnt[maxn], ch[maxn][10], len[maxn], fail[maxn];
    char s[maxn];

    int node(int l) {  // 建立一个新节点，长度为 l
        sz++;
        memset(ch[sz], 0, sizeof(ch[sz]));
        len[sz] = l;
        fail[sz] = cnt[sz] = 0;
        return sz;
    }

    void clear() {  // 初始化
        sz = -1;
        last = 0;
        s[tot = 0] = '$';
        node(0);
        node(-1);
        fail[0] = 1;
    }

    int getfail(int x) {  // 找后缀回文
        while (s[tot - len[x] - 1] != s[tot]) x = fail[x];
        return x;
    }

    void insert(char c) {  // 建树
        s[++tot] = c;
        int now = getfail(last);
        if (!ch[now][c - '0']) {
            int x = node(len[now] + 2);
            fail[x] = ch[getfail(fail[now])][c - '0'];
            ch[now][c - '0'] = x;
        }
        last = ch[now][c - '0'];
        cnt[last]++;
    }

    void solve() {
        long long ans = 0;
        for (int i = sz; i >= 0; i--) {
            cnt[fail[i]] += cnt[i];
        }
    }
} pam1, pam2;  // namespace pam
char s[maxn];

void dfs(int u,int v){
    if(v!=-1)pam1.cnt[u]-=pam2.cnt[v];
    for(int i=0;i<=9;++i){
        if(pam1.ch[u][i]!=0){
            if(v!=-1&&pam2.ch[v][i]!=0){
                dfs(pam1.ch[u][i],pam2.ch[v][i]);
            }else{
                dfs(pam1.ch[u][i],-1);
            }
        }
    }
}

long long solve() {
    long long ans=0;
    for(int i=2;i<=pam1.sz;i++){
        if(pam1.len[i]<=n){
            ans=(ans+1LL*pam1.len[i]*pam1.cnt[i]%mod*pam1.cnt[i]%mod)%mod;
        }
    }
    return ans;
}


signed main() {

    cin >> n;
    pam1.clear();
    pam2.clear();
    scanf("%s", s + 1);
    for (int i = 1; i <= n; i++) {
        pam1.insert(s[i]);
        pam2.insert(s[i]);
    }
    for (int i = 1; i <= n; i++) {
        pam1.insert(s[i]);
    }
    pam1.solve();
    pam2.solve();
    dfs(0,0);
    dfs(1,1);
    cout<<solve()<<endl;
    return 0;
}