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

#ifdef LOCAL
    #define eprintf(...) fprintf(stderr, __VA_ARGS__)
#else
        #define eprintf(...) 42
#endif

#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define repi(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define all(x) (x).begin(),(x).end()
#define foreach(u,v) for(auto (u) : (v))
#define pb push_back
#define mp make_pair
#define mt make_tuple

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<ll, ll> pll;
typedef vector<ll> vl;

const int inf = 1e9;
const ll linf = 1LL<<60;
const ll mod = 1e9 + 7;
const double eps = 1e-9;

/*
*/

struct edge{
  int to, cap, rev;
  edge(int t, int c, int r)
  {
    to = t; cap = c; rev = r;
  }
};

int n, m;
string c[50];
vector<edge> g[2500];
bool used[2500];

void add_edge(int from, int to, int cap)
{
  g[from].pb(edge(to, cap, g[to].size()));
  g[to].pb(edge(from, 0, g[from].size()-1));
}

int dfs(int v, int t, int f)
{
  if(v == t) return f;
  used[v] = true;

  for(auto& e : g[v]){
    if(e.cap > 0 and !used[e.to]){
      int d = dfs(e.to, t, min(f, e.cap));
      if(d > 0){
        e.cap -= d;
        g[e.to][e.rev].cap += d;
        return d;
      }
    }
  }
  return 0;
}

int maxflow(int s, int t)
{
  int flow = 0;
  while(1){
    fill(used, used+n*m, false);
    int f = dfs(s, t, inf);
    if(f == 0) return flow;
    flow += f;
  }
}

int main()
{
  cin >> n >> m;
  rep(i, n) cin >> c[i];

  int s = n * m;
  int t = s + 1;
  int nw = 0, nb = 0;
  rep(i, n) rep(j, m){
    if(c[i][j] == 'w'){
      add_edge(s, m*i+j, 1);
      nw++;
    }else if(c[i][j] == 'b'){
      add_edge(m*i+j, t, 1);
      nb++;
    }
  }

  int dx[] = {1, -1, 0, 0};
  int dy[] = {0, 0, 1, -1};
  rep(i, n) rep(j, m){
    if(c[i][j] == 'w'){
      rep(k, 4){
        int nx = j + dx[k];
        int ny = i + dy[k];
        if(nx < 0 or m <= nx or ny < 0 or n <= ny) continue;
        if(c[ny][nx] == 'b'){
          add_edge(m*i+j, m*ny+nx, 1);
        }
      }
    }
  }

  int max_f = maxflow(s, t);
  int ten = min(nw-=max_f, nb-=max_f);
  cout << 100*max_f+10*ten+(nw+nb-ten*2) << endl;

  return 0;
}