#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <cctype>
#include <functional>
#include <map>
#include <cstring>
using namespace std;
typedef long long ll;

#define reps(i,s,n) for(int (i) = (s); (i) < (n); (i)++)
#define rep(i,n) reps(i,0,n)
const int INF = 1e9;

struct edge {int to,cap,rev;};
const int MAX_V = 1e6;
vector<edge> G[MAX_V];
bool used[MAX_V];

void add_edge(int from,int to,int cap){
    G[from].push_back({to,cap,(int)G[to].size()});
    G[to].push_back({from,0,(int)G[from].size()-1});
}

int dfs(int v,int t,int f){
    if(v==t) return f;
    used[v] = true;
    rep(i,G[v].size()){
        edge &e = G[v][i];
        if(!used[e.to] && e.cap > 0){
            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 max_flow(int s,int t){
    int flow = 0;
    for(;;){
        memset(used,0,sizeof(used));
        int f = dfs(s,t,INF);
        if(f == 0) return flow;
        flow += f;
    }
}

int V,E;
int f,to,c;
int N,M;
vector<string> vec;

int main(){
    int B=0,W=0;
    cin >> N >> M;
    vec.resize(N);
    rep(i,N) cin >> vec[i];

    rep(i,N){
        rep(j,M){
            if(vec[i][j] == 'w'){
                add_edge(10000,i*M+j ,1);
                W++;
            }else if(vec[i][j]=='b'){
                add_edge(i*M+j,10001,1);
                B++;
            }
        }
    }

    rep(i,N) {
        rep(j,M){
            if(vec[i][j] == 'w'){
                if(i > 0){
                    if(vec[i-1][j] == 'b'){
                        add_edge(i*M+j,(i-1)*M+j ,1);
                    }
                } 
                if(i < N-1){
                    if(vec[i+1][j] == 'b'){
                        add_edge(i*M+j,(i+1)*M+j ,1);
                    }
                }
                if(j > 0){
                    if(vec[i][j-1] == 'b'){
                        add_edge(i*M+j,i*M+j-1,1);
                    }
                }
                if(j < M-1){
                    if(vec[i][j+1] == 'b'){
                        add_edge(i*M+j, i*M+j+1,1);
                    }
                }
            }
        }
    }
    int total_f = max_flow(10000,10001);
    int ans = total_f*100;
    ans += min(B-total_f, W-total_f)*10;
    ans += (max(B-total_f, W-total_f) - min(B-total_f, W-total_f) );
    cout << ans << endl;

    return 0;
}