#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <algorithm>
#include <set>
#include <queue>
#include <stack>

using namespace std;

#define pb push_back
#define mp make_pair
#define x first
#define y second

typedef long long ll;
typedef long double db;
typedef pair <int, int> pii;
typedef pair <db, db> pdd;

const int X[8] = {1, 2,  2,  1, -1, -2, -2, -1};
const int Y[8] = {2, 1, -1, -2, -2, -1,  1,  2};
const int N = 20 + 1;

vector < pair <pii, char> > a;
vector <int> w[N];
bool b[N];
int mn = 100, n, m;

bool can(char c, pii f, pii s)
{
  if (c == 'K')
    return (max(abs(s.x - f.x), abs(s.y - f.y)) < 2);
  if (c == 'B')
    return ((s.y - s.x == f.y - f.x) || (s.y + s.x == f.y + f.x));
  if (c == 'R')
    return (s.x == f.x || s.y == f.y);
  if (c == 'Q')
    return ((s.x == f.x || s.y == f.y) || ((s.y - s.x == f.y - f.x) || (s.y + s.x == f.y + f.x)));

  for (int i = 0; i < 8; i++)
    if (f.x + X[i] == s.x && f.y + Y[i] == s.y)
      return true;
  return false;
}

void brute(int x)
{
  if (x == n)
  {
    for (int i = 0; i < n; i++)
      if (b[i])
        for (int j = 0; j < w[i].size(); j++)
          if (b[w[i][j]])
            return;
    int k = 0;
    for (int i = 0; i < n; i++)
      k += b[i];
    mn = min(n - k, mn);
    return;
  }

  b[x] = false;
  brute(x + 1);
  b[x] = true;
  brute(x + 1);
}

int main()
{
  char c;

  cin >> n >> m;

  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++)
    {
      cin >> c;
      if (c != '.')
        a.pb(mp(mp(i, j), c));
    }
  n = a.size();
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++)
      if (i == j)
        continue;
      else if (can(a[i].y, a[i].x, a[j].x))
        w[i].pb(j);

  brute(0);
  cout << mn << endl;

  return 0;
}