#include<bits/stdc++.h>
using namespace std;

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

int n, m, sol, freq[26], dp[1005][1005];
char c, A[1005][1005];
bool ok[1005][1005];

int main(){
    fin >> n >> m;

    for(int i = 1; i <= n; ++i)
        for(int j = 1; j <= n; ++j){
            fin >> A[i][j];
            ok[i][j] = true;
        }

    for(int i = 1; i <= m; ++i)
    for(int j = 1; j <= m; ++j){
        fin >> c;
        ++freq[c - 'a'];
    }

    for(int lit = 0; lit < 26; ++lit){
        for(int i = 1; i <= n; ++i)
        for(int j = 1; j <= n; ++j){
            dp[i][j] = ((A[i][j] - 'a') == lit) + dp[i - 1][j] + dp[i][j - 1] - dp[i - 1][j - 1];
            if(dp[i][j] < freq[lit])
                ok[i][j] = false;
        }
    }

    for(int i = 1; i <= n; ++i)
        for(int j = 1; j <= n; ++j)
            sol += ok[i][j];

    fout << sol;
}