#include<bits/stdc++.h>

#ifndef ONLINE_JUDGE
#include "debug.h"
#else
#define debug(...) 42
#endif

using i64 = long long;

namespace ranges = std::ranges;

template <int Z, char Base>
struct Pam {
    std::vector<std::array<int, Z>> son;
    std::vector<int> link, len, dep, cnt;
    std::string s;
    int half{};

    int cur = 0, tot = 1;

    Pam(int n)
        : son(n + 2), link(n + 2), len(n + 2),
          dep(n + 2), cnt(n + 2) {
        link[0] = 1;
        len[1] = -1;
        half = n / 2;
    }

    Pam(const std::string &s) : Pam(s.size()) {
        for (int i = 0; i < s.size(); i++) {
            add(i, s[i]);
        }
    }

    void assign(int cur, int id) {
        cnt[cur]++;
    }

    int getLink(int x, int i) {
        while (i - len[x] - 1 < 0 or s[i - len[x] - 1] != s[i])
            x = link[x];
        return x;
    }

    void add(int i, char c) {
        c -= Base;
        s.push_back(c);

        int v = getLink(cur, i);

        if (!son[v][c]) {
            link[++tot] = son[getLink(link[v], i)][c];
            son[v][c] = tot;
            len[tot] = len[v] + 2;
            dep[tot] = dep[link[tot]] + 1;
        }

        cur = son[v][c];
        if (i >= half) {assign(cur, i);}
    }

    // Pam 的 linkTree 是 1 为根的
    auto getLinkTree() const {
        std::vector e(tot + 1, std::vector<int>());
        for (int i = 0; i <= tot; i++) {
            if (i != 1)
                e[link[i]].emplace_back(i);
        }
        return e;
    }
};

constexpr int P{998244353};

void solve()
{
    int n; std::cin >> n; std::string s; std::cin >> s; s = s + s;
    Pam<10, '0'> pam(s);
    auto tot{pam.tot}; auto len{pam.len}; auto cnt{pam.cnt}; auto link{pam.link};
    i64 ans{}; for (int i = tot; i >= 0; i--) {
        if (len[i] <= n) {ans += 1LL * cnt[i] * cnt[i] % P * len[i] % P; ans %= P;}
        cnt[link[i]] += cnt[i];
    }
    std::cout << ans << "\n";
}

signed main()
{
   std::cin.tie(nullptr)->sync_with_stdio(false);
   int _(1);
#ifdef tests
   std::cin >> _;
#endif
   while(_--) solve();
   return 0;
}