#include <bits/stdc++.h>
using namespace std;
const int N = 100;
char s[N][N];
int CountWhite[N];
int CountBlue[N];
int CountRed[N];
int NOW[N];
int NOB[N];
int NOR[N];
void Function(char, int);
int main()
{
  int n, m;
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; i++)
  {
    scanf("%s", s[i]+1);
    for (int j = 1; j <= m; j++)
    {
      Function(s[i][j], i);
    }
    NOW[i] = m - CountWhite[i];
    NOB[i] = m - CountBlue[i];
    NOR[i] = m - CountRed[i];
  }
  int ret = NOW[1];
  bool flag = true;
  int i = 2;
  for ( ; i <= n; i++)
  {
    if(CountWhite[i] > CountBlue[i] && flag == false)
    {
      break;
    }
    if(i == n-1)
    {
      break;
    }
    if(CountBlue[i] >= CountWhite[i])
    {
      ret += NOB[i];
      flag = false;
    }
    else
    {
      ret += NOB[i];
    }
  }
  flag = true;
  for ( ; i <= n; i++)
  {
    if(i == n)
    {
      break;
    }
    if(CountBlue[i] > CountRed[i] && flag == false)
    {
      break;
    }
    if(CountBlue[i] >= CountRed[i])
    {
      ret += NOB[i];
      flag = false;
    }
    else
    {
      ret += NOR[i];
    }
  }
  flag = true;
  for ( ; i <= n; i++)
  {
    ret += NOR[i];
  }
  printf("%d\n", ret);
  return 0;
}
void Function(char ch, int line)
{
  if(ch == 'W')
  {
    CountWhite[line]++;
  }
  else if(ch == 'E')
  {
    CountBlue[line]++;
  }
  else
  {
    CountRed[line]++;
  }
  return ;
}