#include <iostream>
#include <iomanip>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <queue>
#include <deque>
#include <cmath>
#include <algorithm>
#include <cassert>
#include <chrono>
#include <random>
#include <string>
#include <numeric>
#include <complex>
#include <tuple>
#include <utility>
#include <bitset>
#include <array>
#include <stack>
#include <sstream>

using namespace std;
typedef long long ll;
 
string to_string(string a) { return '"' + a + '"'; }
string to_string(char a) { return "'" + string(1, a) + "'"; }
string to_string(const char* a) { return to_string((string) a); }
string to_string(bool a) { return a ? "true" : "false"; }
template <class T1, class T2>
string to_string(pair<T1, T2> a) {
    return "(" + to_string(a.first) + ", " + to_string(a.second) + ")";
}
template <class T>
string to_string(T a) {
    bool first = true; string res = "{";
    for (const auto& i : a) {
        if (!first) res += ", ";
        first = false;
        res += to_string(i);
    }
    res += "}";
    return res;
}
void debug_out() { cerr << endl; }
template <class T1, class... T2>
void debug_out(T1 a, T2... b) {
    cerr << " " << to_string(a);
    debug_out(b...);
}
 
#ifdef LOCAL
#define out(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define out(...) 42
#endif

clock_t start_time; void start_timer() { start_time = clock(); }
double get_time() { return (double) (clock() - start_time) / CLOCKS_PER_SEC; }

void Solve();

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
#ifdef LOCAL
    freopen("usr/share/man/man1/input.txt", "r", stdin);
#endif
    start_timer();
    Solve();
#ifdef LOCAL
    cerr << fixed << setprecision(3);
    cerr << endl << "Time spent: " << get_time() << endl;
#endif
    return 0;
}

// do something, stay focused
// look for stupid bugs
// guess, slow, stress
// don't overgeneralize
// don't rush

// don't waste time on standings

// SOLVE THE PROBLEM OR DIE TRYING
// THE SOLUTION IS ALWAYS SIMPLE
// THE CODE IS ALWAYS SHORT

template <int m>
struct mint {
    int x = 0;
    mint(int64_t a = 0) { if (a < 0) a = a % m + m; if (a >= m) a %= m; x = a; }
    friend istream& operator>>(istream& in, mint& a) { int64_t y; in >> y; a = y; return in; }
    friend ostream& operator<<(ostream& out, mint a) { return out << a.x; }
    explicit operator int() const { return x; }
    static int mod_inv(int a, int mod = m) {
        int g = mod, r = a, z = 0, y = 1;
        while (r != 0) { int q = g / r; g %= r; swap(g, r); z -= q * y; swap(z, y); }
        return z < 0 ? z + mod : z;
    }
    mint inv() const { return mod_inv(x, m); }
    friend mint binpow(mint a, int64_t b) { mint res = 1; while (b) { if (b & 1) res *= a; b >>= 1; a *= a; } return res; }
    mint pow(int64_t b) const { return binpow(*this, b); }
    mint operator-() const { return x ? m - x : 0; }
    mint& operator+=(const mint& a) { x += a.x; if (x >= m) x -= m; return *this; }
    mint& operator-=(const mint& a) { x -= a.x; if (x < 0) x += m; return *this; }
    static unsigned fast_mod(uint64_t x, unsigned mod = m) {
#if defined(_WIN32) && !defined(_WIN64)
        // Optimized mod for Codeforces 32-bit machines.
        // x must be less than 2^32 * mod for this to work, so that x / mod fits in a 32-bit integer.
        unsigned x_high = x >> 32, x_low = (unsigned) x; unsigned quot, rem;
        asm("divl %4\n" : "=a" (quot), "=d" (rem) : "d" (x_high), "a" (x_low), "r" (mod));
        return rem;
#else
        return x % mod;
#endif
    }
    mint& operator*=(const mint& a) { x = fast_mod((uint64_t) x * a.x); return *this; }
    mint& operator/=(const mint& a) { return *this *= a.inv(); }
    friend mint operator+(mint a, const mint& b) { return a += b; }
    friend mint operator-(mint a, const mint& b) { return a -= b; }
    friend mint operator*(mint a, const mint& b) { return a *= b; }
    friend mint operator/(mint a, const mint& b) { return a /= b; }
    mint& operator++() { x = x == m - 1 ? 0 : x + 1; return *this; }
    mint& operator--() { x = x == 0 ? m - 1 : x - 1; return *this; }
    mint operator++(int) { mint a = *this; ++*this; return a; }
    mint operator--(int) { mint a = *this; --*this; return a; }
    bool operator==(const mint& a) const { return x == a.x; }
    bool operator!=(const mint& a) const { return x != a.x; }
};

const int mod = 998244353;

#define mi mint<mod>

const int N = 6e6 + 200;
const int K = 10;

int to[N][K];
int len[N];
int link[N];
int s[N];
int sz;
int m;
int last;
int cnt[N];

void init() {
    link[0] = 1;
    len[1] = -1;
    s[m++] = -1;
    sz = 2;
}

int get_link(int v) {
    while (s[m - len[v] - 2] != s[m - 1]) v = link[v];
    return v;
}

void add_letter(int c, int x) {
    s[m++] = c;
    last = get_link(last);
    if (!to[last][c]) {
        len[sz] = len[last] + 2;
        link[sz] = to[get_link(link[last])][c];
        to[last][c] = sz++;
    }
    last = to[last][c];
    cnt[last] += x;
}

vector<pair<int, int>> all;

void calc_cnt() {
    all.clear();
    for (int i = 2; i < sz; i++) {
        all.push_back({len[i], i});
    }
    sort(all.rbegin(), all.rend());
}

string a;

void Solve() {
    all.reserve(N);
    init();
    int n;
    cin >> n;
    cin >> a;
    init();
    for (int i = 0; i <= 1; i++) {
        for (char c : a) {
            add_letter(c - '0', i);
        }
    }
    mi ans = 0;
    calc_cnt();
    for (auto [l, v] : all) {
        cnt[link[v]] += cnt[v];
        if (l <= n) {
            ans += mi(cnt[v]) * mi(cnt[v]) * mi(len[v]);
            
        }
    }
    cout << ans << "\n";
}