#include <bits/stdc++.h>

using i64 = long long;

const i64 mod = 998244353;

struct PAM {
    static constexpr int ALPHABET_SIZE = 11;
    struct Node {
        int len;
        int link;
        int cnt;
        std::array<int, ALPHABET_SIZE> next;
        Node() : len{}, link{}, cnt{}, next{} {}
    };
    std::vector<Node> t;
    int suff;
    std::string s;
    PAM() {
        init();
    }
    void init() {
        t.assign(2, Node());
        t[0].len = -1;
        suff = 1;
        s.clear();
    }
    int newNode() {
        t.emplace_back();
        return t.size() - 1;
    }
    bool add(char c) {
        int pos = s.size();
        s += c;
        int let = c - '0';
        int cur = suff, curlen = 0;
        while (true) {
            curlen = t[cur].len;
            if (pos - 1 - curlen >= 0 && s[pos - 1 - curlen] == s[pos]) {
                break;
            }
            cur = t[cur].link;
        }
        if (t[cur].next[let]) {
            suff = t[cur].next[let];
            return false;
        }
        int num = newNode();
        suff = num;
        t[num].len = t[cur].len + 2;
        t[cur].next[let] = num;
        if (t[num].len == 1) {
            t[num].link = 1;
            t[num].cnt = 1;
            return true;
        }
        while (true) {
            cur = t[cur].link;
            curlen = t[cur].len;
            if (pos - 1 - curlen >= 0 && s[pos - 1 - curlen] == s[pos]) {
                t[num].link = t[cur].next[let];
                break;
            }
        }
        t[num].cnt = 1 + t[t[num].link].cnt;
        return true;
    }
    int next(int p, int x) {
        return t[p].next[x];
    }
    int link(int p) {
        return t[p].link;
    }
    int len(int p) {
        return t[p].len;
    }
    int size() {
        return t.size();
    }
};

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    int n;
    std::cin >> n;

    std::string s;
    std::cin >> s;

    PAM pam;
    std::vector<int> x;
    for (auto c : s) {
        pam.add(c);
    }
    
    for (auto c : s) {
        pam.add(c);
        x.push_back(pam.suff);
    }

    std::vector<int> f(pam.size());
    for (auto v : x) {
        f[v]++;
    }
    
    std::vector<std::vector<int>> adj(pam.size());
    for (int i = 2; i < pam.size(); i++) {
        adj[pam.link(i)].push_back(i);
    }
    
    i64 ans = 0;
    auto dfs = [&](auto self, int x) -> void {
        for (auto y : adj[x]) {
            self(self, y);
            f[x] += f[y];
        }
        if(pam.len(x) <= n)
            ans = (ans + 1LL * pam.len(x) * f[x] % mod * f[x] % mod) % mod;
    };
    dfs(dfs, 1);
    std::cout << ans << "\n";

    return 0;
}