#include #define rep(i,n) for(int i = 0; i < n; i++) using namespace std; typedef pair P; bool g[1000][1000]; int id[1000][1000]; bool did[1000000]; bool checked[1000000]; bool saw[1000000]; int num[1000000]; int n, m; int x = 0; vector edge[1000000]; int func(int a, int type){ saw[a] = true; int ret = 0; if(type == 0) ret += num[a]; rep(i,edge[a].size()){ int e = edge[a][i]; if(checked[e]) continue; if(saw[e]) continue; ret += max(func(e,0),func(e,1)); } return ret; } int main(){ cin >> n >> m; rep(i,n){ string str; cin >> str; rep(j,m){ if(str[j] == 'x') g[i][j] = true; else g[i][j] = false; } } rep(i,n) rep(j,m){ if(!g[i][j]) continue; if(id[i][j] != 0) continue; x++; int cnt = 1; queue

que; que.push(P(i,j)); id[i][j] = x; while(true){ if(que.size() == 0) break; P q = que.front(); que.pop(); for(int k = -1; k <= 1; k++) for(int l = -1; l <= 1; l++){ if(0>q.first+k||q.first+k>=n) continue; if(0>q.second+l||q.second+l>=m) continue; if(id[q.first+k][q.second+l] != 0 || g[q.first+k][q.second+l] == false) continue; que.push(P(q.first+k,q.second+l)); id[q.first+k][q.second+l] = x; cnt++; } } num[x] = cnt; } rep(i,n) rep(j,m){ if(id[i][j] == 0) continue; if(did[id[i][j]]) continue; did[id[i][j]] = true; map ma, ma2, ok; map::iterator it; queue qu; for(int u = i-1; u >= 0; u--){ if(id[u][j] > 0 && id[u][j] != id[i][j]){ ma[id[u][j]] += 1; qu.push(id[u][j]); } } for(int u = j-1; u >= 0; u--){ if(id[i][u] > 0 && id[i][u] != id[i][j]){ ma2[id[i][u]] += 1; } } while(true){ if(qu.size() == 0) break; int q = qu.front(); qu.pop(); if(ma[q]%2 == 0) continue; if(ma2[q]%2 == 0) continue; edge[id[i][j]].push_back(q); edge[q].push_back(id[i][j]); break; } } int ans = 0; rep(i,x){ int t = i+1; if(checked[t]) continue; int f[2]; rep(u,2){ rep(j,x) saw[j+1] = checked[j+1]; f[u] = func(t,u); } ans += max(f[0],f[1]); rep(j,x) checked[j+1] = saw[j+1]; } cout << ans << endl; }