#include <bits/stdc++.h>

using namespace std;

ifstream fin("matrix.in");
ofstream fout("matrix.out");

int n, m, fr[30], fr2[30], x, y, contor;
char a[1005][1005], b[1005][1005];

int DaniMocanuTotceamavutOfficialVideoHiT2019()
{
    for (char ch = 'a'; ch <= 'z'; ++ch)
    {
        if (fr[ch - 'a'] != fr2[ch - 'a'])
        {
            cout << ch << "\n";
            return 0;
        }
    }
    return 1;
}

void MoveRight()
{
    for (int k = 0; k < m; ++k)
    {
        fr2[a[x + k][y] - 'a']--;
        fr2[a[x + k][y + m] - 'a']++;
    }
    ++y;
}

void MoveLeft()
{
    for (int k = 0; k < m; ++k)
    {
        fr2[a[x + k][y + m - 1] - 'a']--;
        fr2[a[x + k][y - 1] - 'a']++;
    }
    --y;
}

void MoveDown()
{
    for (int k = 0; k < m; ++k)
    {
        fr2[a[x][y + k] - 'a']--;
        fr2[a[x + m][y + k] - 'a']++;
    }
    ++x;
}

int main()
{
    fin >> n >> m;
    for (int i = 1; i <= n; ++i)
    {
        for (int j = 1; j <= n; ++j)
        {
            fin >> a[i][j];
        }
    }
    for (int i = 1; i <= m; ++i)
    {
        for (int j = 1; j <= m; ++j)
        {
            fin >> b[i][j];
            fr[b[i][j] - 'a']++;
            fr2[a[i][j] - 'a']++;
        }
    }
    x = 1;
    y = 1;
    while (true)
    {
        for (int k = 1; k <= n - m + 1; ++k)
        {
            contor = contor + DaniMocanuTotceamavutOfficialVideoHiT2019();
            if (k != n - m + 1)
                MoveRight();
        }
        if (x + m > n)
        {
            break;
        }
        MoveDown();
        for (int k = 1; k <= n - m + 1; ++k)
        {
            contor = contor + DaniMocanuTotceamavutOfficialVideoHiT2019();
            if (k != n - m + 1)
                MoveLeft();
        }
        if (x + m > n)
        {
            break;
        }
        MoveDown();
    }
    fout << contor << "\n";
    fin.close();
    fout.close();
    return 0;
}