#include <bits/stdc++.h>
#define endl "\n"
using namespace std;

using ll = long long;
const int MOD = 998244353;
const int N = 3e6 + 5;

string s;

struct PAM {
    int s[N * 2];
    int n, tot, last;
    struct Palindromic_Tree {
        int next[10];
        int len;
        int cnt; 
        int size;
        int fail;   // [最长回文后缀] 在回文树上对应的节点
    } tr[N * 4];

    PAM() {
        s[0] = 10;
        tr[0].fail = 1;
        tr[1].len = -1;
        tot = 1;
    }

    int getfail(int x) {
        while (s[n - tr[x].len - 1] != s[n]) {
            x = tr[x].fail;
        }
        return x;
    }

    void insert(int x, bool flag) {
        s[++n] = x;
        int p = getfail(last);
        while (!tr[p].next[x]) {
            int cur = ++tot;
            tr[cur].len = tr[p].len + 2;
            tr[cur].fail = tr[getfail(tr[p].fail)].next[x];
            tr[cur].size = tr[tr[cur].fail].size + 1;
            tr[p].next[x] = cur;
        }
        last = tr[p].next[x];
        if (flag)
            tr[last].cnt++; 
    }

    void count() {
        for (int i = tot; i >= 2; i--) {
            tr[tr[i].fail].cnt = (1ll * tr[tr[i].fail].cnt + tr[i].cnt) % MOD;
        }
    }

    int getUniqueCount() {
        return tot - 1;
    }

    int cal(int n, string& t) {
        for (int i = 0; i < 2 * n; i++) {
            insert(t[i % n] - '0', i >= n);
        }

        count();
        
        int ans = 0;
        for (int i = 2; i <= tot; i++) {
            if (tr[i].len <= n)
                ans = (ans + 1ll * tr[i].len * tr[i].cnt % MOD * tr[i].cnt % MOD) % MOD;
        }
        return ans;
    }
} pam;

signed main() {
    ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);

    int n;
    cin >> n;
    cin >> s;
    cout << pam.cal(n, s) << endl;
}