/* Problem URL: https://codeforces.com/gym/106159/problem/A */

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;

#define V vector

#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)

#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)

#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()

using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;

using ll = long long;

using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;

template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
    os << vec[0];
    for (size_t i = 1; i < vec.size(); i++) {
        os << ' ' << vec[i];
    }
    os << '\n';
    return os;
}

template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
    for (auto &i : vec) {
        is >> i;
    }
    return is;
}

template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
    for (auto &i : vec) {
        os << i[0];
        for (size_t j = 1; j < i.size(); j++) {
            os << ' ' << i[j];
        }
        os << '\n';
    }
    return os;
}

template<class v>
auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
    for (auto &i : vec) {
        for (auto &j : i) {
            is >> j;
        }
    }
    return is;
}

const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;


void pre()
{

}

ll mod = 998244353;

#define TEST 0

void solve()
{
    ll n, m;
    cin >> n >> m;
    string s;
    cin >> s;

    auto fpow = [&](ll a, ll p) {
        ll ans = 1;
        rep(i, 61) {
            if ((p >> i) & 1) {
                ans *= a;
                ans %= mod;
            }

            a *= a;
            a %= mod;
        }

        return ans;
    };

    // ll total = fpow(26, n - m) * (n - m + 1) % mod;
    // // cout << fpow(26, n - m) * (n - m + 1) % mod << '\n';
    // // cout << fpow(26, n - m) << '\n';
    //
    // nrep(i, 1, m - 1) {
    //     if (s.substr(i, m - 1) != s.substr(0, m - i)) {
    //         continue;
    //     }
    //
    //     string tmp1 = s.substr(0, i);
    //     string tmp2 = s.substr(m - i);
    //     reverse(all(tmp2));
    //     if (tmp1 != tmp2) {
    //         continue;
    //     }
    //
    //     int size = m + i;
    //     if (size > n) {
    //         break;
    //     }
    //
    //     total -= fpow(26, n - size) * (n - size + 1) % mod;
    //     total += mod * (total < 0);
    // }
    //
    // if (2 * m > n) {
    //     cout << total << '\n';
    //     return;
    // }
    //
    // ll rem = fpow(26, n - m * 2);
    //
    //
    // cout << total << '\n';

    // ll total = fpow(26, n);
    // rep(i, m) {
    //     ll now = fpow(26, i);
    //     ll cur = n - i;
    //
    //     ll inv = (cur + m - 1) / m % mod;
    //     ll val = (cur / m * (m - 1) + max(cur % m - 1, 0LL)) % mod;
    //
    //     total -= now * fpow(25, inv) % mod * fpow(26, val) % mod;
    //     total += mod * (total < 0);
    // }
    //
    // cout << total << '\n';

    vl fact(101);
    fact[0] = 1;
    nrep(i, 1, 101) {
        fact[i] = (fact[i - 1] * i) % mod;
    }

    vl inv(101);
    inv[0] = 1;
    inv[1] = 1;
    nrep(i, 2, 101) {
        inv[i] = (mod - mod / i) * inv[mod % i] % mod;
    }
    nrep(i, 2, 101) {
        inv[i] = (inv[i] * inv[i - 1]) % mod;
    }

    auto comb = [&](ll n, ll k) {
        return fact[n] * inv[k] % mod * inv[n - k] % mod;
    };

    auto comb2 = [&](ll n, ll k) {
        ll ans = n;
        ll div = 1;
        nrep(i, 2, k + 1) {
            ans = (ans * (n - i + 1)) % mod;
            div = (div * i) % mod;
        }

        return ans * fpow(div, mod - 2) % mod;
    };

    ll rem = 0;
    ll cur = (n + m - 1) / m;
}

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

    pre();

    int t;
    (TEST && cin >> t) || (t = 1);
    while (t--) {
        solve();
    }
}