#include #include #include #include #include #include #include #include #define REP(i,k,n) for(int i=k;i P; int w,h; vector s; bool can(int y,int x) { if(0 <= y && y < h && 0 <= x && x < w) return true; return false; } int main() { cin >> h >> w; s.resize(h); rep(i,h) { cin >> s[i]; } bool f = false; rep(dy,h) { if(f) break; REP(dx,-w+1,w) { if(dy == 0 && dx == 0) continue; bool used[55][55]; memset(used,0,sizeof(used)); bool flag = true; rep(i,h) { rep(j,w) { if(s[i][j] == '#' && !used[i][j]) { int y = i + dy; int x = j + dx; if(can(y,x) && !used[y][x] && s[y][x] == '#') { used[y][x] = true; } else { flag = false; } } } } if(flag) { f = true; } } } if(f) cout << "YES" << endl; else cout << "NO" << endl; return 0; }