#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define X first
#define Y second
#define pb push_back
#define SZ(a) ((int)a.size())
#define ALL(v) v.begin(), v.end()

template<int MAXN, ll P, ll RT>
struct NTT {
    ll w[MAXN];
    ll mpow(ll a, ll n) {
        ll res = 1;
        for (; n; n >>= 1, a = a * a % P)
            if (n & 1)
                res = res * a % P;
        return res;
    }
    ll minv(ll a) {
        return mpow(a, P - 2);
    }
    NTT() {
        ll dw = mpow(RT, (P - 1) / MAXN);
        w[0] = 1;
        for (int i = 1; i < MAXN; ++i) w[i] = w[i - 1] * dw % P;
    }
    void bitrev(ll *a, int n) {
        int i = 0;
        for (int j = 1; j < n - 1; ++j) {
            for (int k = n >> 1; (i ^= k) < k; k >>= 1);
            if (j < i) swap(a[i], a[j]);
        }
    }
    void operator()(ll *a, int n, bool inv = false) {
        bitrev(a, n);
        for (int L = 2; L <= n; L <<= 1) {
            int dx = MAXN / L, dl = L >> 1;
            for (int i = 0; i < n; i += L) {
                for (int j = i, x = 0; j < i + dl; ++j, x += dx) {
                    ll tmp = a[j + dl] * w[x] % P;
                    if ((a[j + dl] = a[j] - tmp) < 0) a[j + dl] += P;
                    if ((a[j] += tmp) >= P) a[j] -= P;
                }
            }
        }
        if (inv) {
            reverse(a + 1, a + n);
            ll invn = minv(n);
            for (int i = 0; i < n; ++i) a[i] = a[i] * invn % P;
        }
    }
};

const int N = 1 << 19;
const ll MOD = 998244353;

NTT<N, MOD, 3> ntt;
ll arr[N], brr[N];
int mch[N];
ll dp[N];

int main() {
    ios::sync_with_stdio(0), cin.tie(0);
    int o, k;
    string a, b;
    cin >> o >> k >> a >> b;
    reverse(ALL(b));
   
    auto proc = [&](char s, char t) {
        fill_n(arr, N, 0);
        fill_n(brr, N, 0);
        for (int i = 0; i < SZ(a); ++i)
            arr[i] = (a[i] == t);
        for (int i = 0; i < SZ(b); ++i)
            brr[i] = (b[i] == s);
        ntt(arr, N), ntt(brr, N);
        for (int i = 0; i < N; ++i)
            arr[i] = arr[i] * brr[i] % MOD;
        ntt(arr, N, true);
        for (int i = SZ(b) - 1; i < SZ(a); ++i)
            mch[i] += arr[i];
    };

    auto cal = [&](ll amt, int t) {
        return amt >> min(t, 60); 
    };

    proc('o', 'k');
    proc('k', 'o');
    ll sumo = 0, sumk = 0;
    for (int i = 1; i <= SZ(a); ++i) {
        if (a[i - 1] == 'o') ++sumo;
        else ++sumk;
        if (i > SZ(b)) {
            if (a[i - SZ(b) - 1] == 'o') --sumo;
            else --sumk;
        }
        if (i >= SZ(b))
            dp[i] = dp[i - SZ(b)] + cal(sumo * o + sumk * k, mch[i - 1]);
        dp[i] = max(dp[i], dp[i - 1]);
    }

    cout << dp[SZ(a)] << "\n";
}