unionFind u('m',1d6,1);
ll@h,@w;
string@g[h];
rep(y,h){
	rep(x,w){
		if(y&&g[y-1][x]==g[y][x])u(y*w+x,(y-1)*w+x);
		if(x&&g[y][x-1]==g[y][x])u(y*w+x,y*w+(x-1));
	}
}
rep(y,h){
	rep(x,w){
		wtN(u.size(y*w+x)<4?g[y][x]:'.');
	}
	wt("");
}