#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
// using mint = modint1000000007;
// const int mod = 1000000007;
// using mint = modint998244353;
// const int mod = 998244353;
// const int INF = 1e9;
// const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i, l, r) for (int i = (l); i < (r); ++i)
#define rrep(i, n) for (int i = (n)-1; i >= 0; --i)
#define rrep2(i, l, r) for (int i = (r)-1; i >= (l); --i)
#define all(x) (x).begin(), (x).end()
#define allR(x) (x).rbegin(), (x).rend()
#define P pair<int, int>
template<typename A, typename B> inline bool chmax(A &a, const B &b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A &a, const B &b) { if (a > b) { a = b; return true; } return false; }
const int dx[8] = { 0,1,0,-1,1,1,-1,-1 };
const int dy[8] = { 1,0,-1,0,1,-1,1,-1 };
int main() {
	std::ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
	int h, w; cin >> h >> w;
	vector<string>s(h);
	rep(i, h)cin >> s[i];
	int st = h * w;
	int ed = st + 1;
	mf_graph<int> mf(ed + 1);
	int l = 0, r = 0;
	rep(i, h)rep(j, w) {
		if (s[i][j] == 'w')mf.add_edge(st, i*w + j, 1), l++;
		else if (s[i][j] == 'b')mf.add_edge(i*w + j, ed, 1), r++;
	}
	rep(i, h)rep(j, w) {
		if (s[i][j] != 'w')continue;
		rep(t, 4) {
			int ni = i + dx[t];
			int nj = j + dy[t];
			if (ni < 0 || ni >= h)continue;
			if (nj < 0 || nj >= w)continue;
			if (s[ni][nj] != 'b')continue;
			mf.add_edge(i * w + j, ni*w + nj, 1);
		}
	}
	int e = mf.flow(st, ed);
	int e2 = min(l, r) - e;
	int e3 = l + r - e * 2 - e2 * 2;
	long long ans = e * 100 + e2 * 10 + e3;
	cout << ans << endl;
	return 0;
}