#include <bits/stdc++.h>

#define long long long int
#define DEBUG
using namespace std;

// @author: pashka

long mod = 998244353;

const int maxn = 6000010;
const int sigma = 10;
int n = 0;
char s[maxn];
long nm1[maxn];
long nm2[maxn];

struct palindrome_tree {
    struct state {
        int len, link;
        int to[sigma];
        long num;

        state() : len(-1), link(-1) {}
    } st[maxn];

    int last, sz;

    palindrome_tree() : last(1), sz(2) { st[1].len = st[1].link = 0; }

    int add_letter() {
        char c = s[n - 1];
        int p = last;
        while (p != -1 && c != s[n - st[p].len - 2]) p = st[p].link;
//        if (st[p].len == 5) {
//            cout << "!!!\n";
//        }
        if (p == -1) {
            last = 1;
            st[last].num++;
//            cout << (int)c << " " << last << " " << st[last].len << "\n";
            return 0;
        }
        int ret = 0;
        if (!st[p].to[c]) {
            ret = 1;
            int q = last = sz++;
            st[p].to[c] = q;
            st[q].len = st[p].len + 2;
            do
                p = st[p].link;
            while (p != -1 && c != s[n - st[p].len - 2]);
            if (p == -1)
                st[q].link = 1;
            else
                st[q].link = st[p].to[c];
        } else
            last = st[p].to[c];
        st[last].num++;
//        cout << (int)c << " " << last << " " << st[last].len << "\n";
        return ret;
    }
};

palindrome_tree me;

int main() {
    ios::sync_with_stdio(false);
    int nn;
    cin >> nn;
    string ss;
    cin >> ss;
    ios::sync_with_stdio(0);
    s[n++] = '#';
    {
        int i = 0;
        while ((s[n++] = ss[i++]) != 0) {
            s[n - 1] -= '0';
            me.add_letter();
        }
    }
    n--;
    for (int i = me.sz - 1; i > 0; i--) {
        nm1[i] += me.st[i].num;
        nm1[me.st[i].link] += nm1[i];
    }
    {
        int i = 0;
        while ((s[n++] = ss[i++]) != 0) {
            s[n - 1] -= '0';
            me.add_letter();
        }
    }
    for (int i = me.sz - 1; i > 0; i--) {
        nm2[i] += me.st[i].num;
        nm2[me.st[i].link] += nm2[i];
    }

    long res = 0;
    for (int i = 0; i < me.sz; i++) {
        if (me.st[i].len > nn) continue;
        if (me.st[i].len <= 0) continue;
        long num = nm2[i] - nm1[i];
//        cout << me.st[i].len << " " << nm1[i] << " " << nm2[i] << "\n";
        long r = num;
        r %= mod;
        r *= r;
        r %= mod;
        r *= me.st[i].len;
        r %= mod;
//        cout << r << "\n";
        res += r;
        res %= mod;
    }
    cout << res << "\n";
    return 0;
}