#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define rep(i, n) for (int i = 0; i < n; i++) #define rep1(i, n) for (int i = 1; i < n + 1; i++) #define rev(i, n) for (int i = n - 1; i >= 0; i--) #define all(A) A.begin(), A.end() #define itr(A, l, r) A.begin() + l, A.begin() + r #define debug(var) cout << #var << " = " << var << endl; typedef long long ll; template ostream &operator<<(ostream &os, const pair &p) { os << "(" << p.first << "," << p.second << ")"; return os; } template istream &operator>>(istream &is, pair &p) { is >> p.first >> p.second; return is; } template ostream &operator<<(ostream &os, const vector &v) { for (int i = 0; i < (int)v.size(); i++) { os << v[i] << (i + 1 != (int)v.size() ? " " : ""); } return os; } template ostream &operator<<(ostream &os, const vector> &v) { for (int i = 0; i < (int)v.size(); i++) { os << v[i] << endl; } return os; } template ostream &operator<<(ostream &os, const vector>> &v) { int n = v.size(); int m = v[0].size(); int p = v[0][0].size(); rep(k, p) { os << "k = " << k << endl; rep(i, n) { rep(j, m) { os << v[i][j][k]; if (j < m - 1) { os << " "; } else { os << endl; } } } } return os; } template istream &operator>>(istream &is, vector &v) { for (T &in : v) is >> in; return is; } template ostream &operator<<(ostream &os, map &mp) { for (auto &[key, val] : mp) { os << key << ":" << val << " "; } cout << endl; return os; } template ostream &operator<<(ostream &os, set st) { auto itr = st.begin(); for (int i = 0; i < (int)st.size(); i++) { os << *itr << (i + 1 != (int)st.size() ? " " : ""); itr++; } return os; } template ostream &operator<<(ostream &os, multiset st) { auto itr = st.begin(); for (int i = 0; i < (int)st.size(); i++) { os << *itr << (i + 1 != (int)st.size() ? " " : ""); itr++; } return os; } template ostream &operator<<(ostream &os, queue q) { while (q.size()) { os << q.front() << " "; q.pop(); } return os; } template ostream &operator<<(ostream &os, deque q) { while (q.size()) { os << q.front() << " "; q.pop_front(); } return os; } template ostream &operator<<(ostream &os, stack st) { while (st.size()) { os << st.top() << " "; st.pop(); } return os; } template ostream &operator<<(ostream &os, priority_queue pq) { while (pq.size()) { os << pq.top() << " "; pq.pop(); } return os; } template ostream &operator<<(ostream &os, priority_queue, greater> mpq) { while (mpq.size()) { os << mpq.top() << " "; mpq.pop(); } return os; } int main(){ int h,w; cin >> h >> w; vector> maze(h,vector(w)); cin >> maze; // cout << maze << endl; vector> seen(h,vector(w)); vector> dist(h,vector(w)); rep(i,h){ rep(j,w){ if(seen[i][j]){ continue; } vector dx = {1,-1,0,0}; vector dy = {0,0,1,-1}; set> st; seen[i][j] = true; st.insert({i,j}); char head = maze[i][j]; auto dfs = [&](auto dfs, int cx,int cy)->int{ int ans = 1; rep(k,4){ int nx = cx + dx[k]; int ny = cy + dy[k]; if(nx<0 || h<=nx){ continue; } if(ny<0 || w<=ny){ continue; } if(seen[nx][ny]){ continue; } if(maze[nx][ny] != head){ continue; } seen[nx][ny] = true; st.insert({nx,ny}); ans += dfs(dfs,nx,ny); } return ans; }; int tmp = dfs(dfs,i,j); // debug(tmp); if(tmp >= 4){ for(auto [cx,cy] : st){ maze[cx][cy] = '.'; } } } } // cout << maze << endl; for(auto &ans : maze){ for(auto a : ans){ cout << a; } cout << endl; } }