#include <algorithm>
#include <iostream>
#include <vector>
#include <set>
using namespace std;
template<class T> ostream& operator<<(ostream& os, const vector<T>& vec) { for (auto &vi: vec) os << vi << " "; return os; }

int main() {
    int h, w; cin >> h >> w;
    vector<string> s(h);
    for (auto &si: s) cin >> si;
    vector<string> field(h + 2, string(w + 2, '.'));    // .x
    for (int i = 0; i < h; i++) field[i + 1] = '.' + s[i] + '.';
    h += 2, w += 2;
    vector<vector<int>> visited(h, vector<int>(w, -1));
    vector<set<int>> g;
    auto dfs = [&](auto dfs, int i, int j, int id, int &cnt) {
        if (~visited[i][j]) return ;
        visited[i][j] = id, cnt++;
        for (int di: {-1, 0, 1}) for (int dj: {-1, 0, 1}) {
            if (abs(di) + abs(dj) > 1 + (field[i][j] == 'x')) continue;
            int ni = i + di, nj = j + dj;
            if (ni < 0 || ni >= h || nj < 0 || nj >= w) continue;
            if (field[ni][nj] == field[i][j]) dfs(dfs, ni, nj, id, cnt);
            else if (~visited[ni][nj]) g[visited[ni][nj]].emplace(id);
        }
    };
    int id = 0;
    vector<int> num;
    for (int i = 0; i < h; i++) for (int j = 0; j < w; j++) {
        if (visited[i][j] == -1) {
            int cnt = 0;
            dfs(dfs, i, j, id, cnt);
            num.emplace_back(cnt);
            g.resize(++id);
        }
    }
    vector<vector<int>> dp(id, vector<int>(2));
    auto dfs2 = [&](auto dfs2, int u) -> int {
        dp[u][1] = num[u];
        for (int v: g[u]) for (int w: g[v]) {
            dp[u][0] += dfs2(dfs2, w);
            dp[u][1] += dp[w][0];
        }
        return max(dp[u][0], dp[u][1]);
    };
    int ans = 0;
    for (int u: g[0]) ans += dfs2(dfs2, u);
    cout << ans << endl;
    return 0;
}