#include<cstdio>
#include<iostream>
#include<algorithm>
#include<string>
#include<cstring>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
#include<numeric>
#include<limits>
#include<iterator>

#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define rep(i,n) for(int i=0; i<n; i++)
#define FOR(i,a,n) for(int i=a; i<n; i++)

using namespace std;
typedef long long ll;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<ll, char> plc;
typedef pair<string, string> pss;

const int INF = 1e9;
const int MAX_V = 3000;

struct Flow {
	struct edge {
		int to, cap, rev;
	};
	vector<edge> G[MAX_V];//隣接リスト
	bool used[MAX_V];

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

	//増加パスを探す
	int dfs(int v, int t, int f) {
		if (v == t)return f;
		used[v] = true;
		for (int i = 0; i < G[v].size(); i++) {
			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;
	}

	//sからtへの最大流
	int max_flow(int s, int t) {
		int flow = 0;
		while (1) {
			memset(used, 0, sizeof(used));
			int f = dfs(s, t, INF);
			if (f == 0)return flow;
			flow += f;
		}
	}
};

string board[55];
int dy[] = { 1,0,0,-1 };
int dx[] = { 0,1,-1,0 };
int n, m;

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

	int s = n * m;
	int t = n * m + 1;
	int numw = 0, numb = 0;
	Flow mf;
	//s -> w  b -> t
	rep(i, n)rep(j, m) {
		if (board[i][j] == 'w') {
			mf.add_edge(s, m*i + j, 1);
			numw++;
		}
		else if (board[i][j] == 'b') {
			mf.add_edge(m*i+j,t,1);
			numb++;
		}
	}

	// x -> y
	rep(i, n)rep(j, m) {
		if (board[i][j] == 'w') {
			rep(k, 4) {
				int ny = i + dy[k], nx = j + dx[k];
				if (!(0 <= ny && ny < n && 0 <= nx && nx < m))continue;
				if (board[ny][nx] == 'b')
					mf.add_edge(m*i + j, m*ny + nx, 1);
			}
		}
	}

	int max_f = mf.max_flow(s, t);
	int nw = numw - max_f, nb = numb - max_f;
	int two = min(nw, nb);
	int one = nw + nb - (two) * 2;
	cout << 100 * max_f +  10*two + one << endl;
	return 0;
}