#include <iostream>
#include <vector>
#include <set>
#include <queue>
#include <stack>
#include <math.h>
#include <cassert>
#include <bitset>
#include <map>
#include <algorithm>
#include <iterator>
#include <string>
#include <utility>
#include <numeric>
#include <regex>
#include <complex>
#include <atcoder/maxflow>
using namespace atcoder;
using namespace std;
using ll=long long;
using ull=unsigned long long;
using P=pair<ll,ll>;
template<typename T>using minque=priority_queue<T,vector<T>,greater<T>>;
template<typename T>bool chmax(T &a,const T &b){return (a<b?(a=b,true):false);}
template<typename T>bool chmin(T &a,const T &b){return (a>b?(a=b,true):false);}
template<typename T1,typename T2>
ostream &operator<<(ostream &os,const pair<T1,T2>&p){
  os<<p.first<<" "<<p.second;
  return os;
}
template<typename T1,typename T2>
istream &operator>>(istream &is,pair<T1,T2>&p){
  is>>p.first>>p.second;
  return is;
}
template<typename T>
istream &operator>>(istream &is,vector<T> &a){
  for(auto &i:a)is>>i;
  return is;
}
#define reps(i,a,n) for(int i=(a);i<(n);i++)
#define rep(i,n) reps(i,0,n)
#define all(x) x.begin(),x.end()
ll myceil(ll a,ll b){return (a+b-1)/b;}
int main(){
  int h,w;
  cin>>h>>w;
  vector<string>s(h);
  cin>>s;
  mf_graph<int>g(h*w+2);
  rep(i,h)rep(j,w)if(s[i][j]!='.'){
    if(s[i][j]=='w')g.add_edge(h*w,i*w+j,1);
    else g.add_edge(i*w+j,h*w+1,1);
  }
  rep(i,h)rep(j,w)if(s[i][j]=='w'){
    if(i<h-1&&s[i+1][j]=='b')g.add_edge(i*w+j,(i+1)*w+j,1);
    if(0<i&&s[i-1][j]=='b')g.add_edge(i*w+j,(i-1)*w+j,1);
    if(j<w-1&&s[i][j+1]=='b')g.add_edge(i*w+j,i*w+j+1,1);
    if(0<j&&s[i][j-1]=='b')g.add_edge(i*w+j,i*w+j-1,1);
  }
  int ans=g.flow(h*w,h*w+1);
  int a=0,b=0;
  rep(i,h)rep(j,w){
    if(s[i][j]=='w')a++;
    if(s[i][j]=='b')b++;
  }
  a-=ans,b-=ans;
  ans*=100;
  if(a>b)swap(a,b);
  ans+=10*a;
  ans+=b-a;
  cout<<ans<<endl;
}