#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;

struct FlowEdge{
    int to, cap, rev;
    FlowEdge(int to_, int cap_, int rev_):to(to_),cap(cap_),rev(rev_){ }
};
class FordFulkerson{
public:
    FordFulkerson(){}

    FordFulkerson(int n) : G(n), used(n){}

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

    int get(int s, int t){
        int f = 1, res = 0;
        while (f){
            fill(begin(used), end(used), false);
            f = dfs(s, t, INT_MAX);
            res += f;
        }
        return res;
    }
private:

    vector<vector<FlowEdge>> G;
    vector<bool> used;

    int dfs(int v, int t, int f){
        if (v == t) return f;
        used[v] = 1;
        for (auto &e : G[v]){
            if (!used[e.to] && e.cap > 0){
                int d = dfs(e.to, t, min(e.cap, f));
                if (d > 0){
                    e.cap -= d;
                    G[e.to][e.rev].cap += d;
                    return d;
                }
            }
        }
        return 0;
    }
};

int maxBipartiteMatching(int n, int m, const vector<int> &u, const vector<int> &v){
    const int source = 0, sink = 1, offN = 2, offM = n + 2;
    const int V = n + m + 2, cap = 1;
    FordFulkerson maxFlow(V);
    for(int i = 0; i < n; ++i){
        maxFlow.add(source, i + offN, cap);
    }
    for(int i = 0; i < m; ++i){
        maxFlow.add(i + offM, sink, cap);
    }
    for(int i = 0; i < (int)u.size(); ++i){
        maxFlow.add(u[i] + offN, v[i] + offM, cap);
    }
    return maxFlow.get(source, sink);
}

string nstr(){
    static const int MAX_LEN = 101;
    static char res_[MAX_LEN];
    scanf("%s",res_);
    return string(res_);
}

int ww[51][51], bb[51][51];

int main(){
    int H, W;
    cin >> H >> W;
    vector<string> S(H);
    rep(y, H)S[y] = nstr();

    int wn = 0, bn = 0;
    MEM(ww, -1);
    MEM(bb, -1);
    rep(y, H)rep(x, W){
        if(S[y][x] == 'w')ww[y][x] = wn++;
        else if(S[y][x] == 'b')bb[y][x] = bn++;
    }

    vi us, vs;
    rep(y, H)rep(x, W){
        if(ww[y][x] == -1)continue;
        if(x > 0 && bb[y][x - 1] != -1){
            us.push_back(ww[y][x]);
            vs.push_back(bb[y][x - 1]);
        }
        if(x < W-1 && bb[y][x+1] != -1){
            us.push_back(ww[y][x]);
            vs.push_back(bb[y][x+1]);
        }
        if(y > 0 && bb[y-1][x] != -1){
            us.push_back(ww[y][x]);
            vs.push_back(bb[y-1][x]);
        }
        if(y < H-1 && bb[y+1][x] != -1){
            us.push_back(ww[y][x]);
            vs.push_back(bb[y+1][x]);
        }
    }
    
    int ps = maxBipartiteMatching(wn, bn, us, vs);
    wn -= ps;
    bn -= ps;
    int ans = ps * 100;
    int mi = min(wn, bn);
    ans += mi * 10;
    wn -= mi;
    bn -= mi;
    ans += wn + bn;
    cout << ans << endl;
}