#include <bits/stdc++.h>

using namespace std;

#define SZ(x) ((int)((x).size()))
#define lb(x) ((x) & (-(x)))
#define bp(x) __builtin_popcount(x)
#define bpll(x) __builtin_popcountll(x)
#define mkp make_pair
#define pb push_back
#define fi first
#define se second
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ll, int> pli;
typedef pair<ll, ll> pll;
typedef pair<double, int> pdi;

const int Mod = 998244353;

struct PAM {
    string s;
    int lst, tot, n;
    vector<int> fa, len, sz, cnt, pos;
    vector<array<int, 10>> ch;
    /*
    - len[i] :  the length of the longest palindrome string end with i
    - sz[i]  :  the number of the palindrome string end with i
    - cnt[i] :  the occurrence number of the longest palindrome string end with i
    - fa[i]  :  i 的回文后缀链接
    - pos[i] :  下标为 i 的字符在回文树上对应的结点
    - st     :  fa 的倍增数组
    */
    PAM(){}
    PAM(string s): s(s), n(s.length() + 2) {    // String s (Index from 0)
        fa.resize(n); len = sz = cnt = pos = fa;
        ch = vector(n, array<int, 10>());
        len[0] = 0; len[1] = -1;
        fa[0] = 1; fa[1] = 0;
        lst = 0; tot = 1;
    }
    int get_fail(int x, int now) {
        while (s[now - len[x] - 1] != s[now]) {
            x = fa[x];
        }        
        return x;
    }
    void insert(int c, int now) {
        int p = get_fail(lst, now);
        if (!ch[p][c]) {
            len[++tot] = len[p] + 2;
            int tmp = get_fail(fa[p], now);
            fa[tot] = ch[tmp][c];
            sz[tot] = sz[fa[tot]] + 1;
            ch[p][c] = tot;
        }
        lst = ch[p][c];
        cnt[lst] += 1;
        pos[now] = ch[p][c];
    }
    void init() {
        for (int i = 0; i < SZ(s); i++) {
            insert(s[i] - '0', i);
        }
        for (int i = tot; i >= 0; i--) {
            cnt[fa[i]] += cnt[i];
        }
    }
};

void solve() {
    int n;
    string s;
    cin >> n >> s;

    PAM pam1(s);
    PAM pam2(s + s);
    pam1.init();
    pam2.init();

    ll ans = 0;
    vector mp(pam2.tot + 1, false);
    for (int i = 0; i < n; i++) {
        int u = pam2.pos[i];
        int len = pam2.len[u];
        int cnt = pam2.cnt[u];
        if (mp[u]) {
            continue;
        }
        mp[u] = true;

        int c = cnt - pam1.cnt[pam1.pos[i]];

        (ans += 1ll * c * c % Mod * len) %= Mod;
    }

    for (int i = n; i < 2 * n; i++) {
        int u = pam2.pos[i];
        int len = pam2.len[u];
        int cnt = pam2.cnt[u];
        if (mp[u]) {
            continue;
        }
        mp[u] = true;

        if (len > n) {
            continue;
        }

        int c = cnt;
        (ans += 1ll * c * c % Mod * len) %= Mod;
    }

    cout << ans << '\n';
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    int T = 1;
    while (T--) solve();
    return 0;
}