//
using System;
using System.Linq;
using System.Collections.Generic;
public class Hello{
    public static void Main(){
        var line = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
        var H = line[0];
        var W = line[1];
        
        var S = new string[H];
        for(var i = 0;i < H;i++){
            S[i] = Console.ReadLine();
        }
        
        for(var i = 1;i < H - 1;i++){
            for(var j = 1;j < W - 1;j++){
                if(S[i][j] == '.' && 
                    S[i - 1][j] == '.' &&
                    S[i][j + 1] == '.' &&
                    S[i + 1][j] == '.' &&
                    S[i][j - 1] == '.')
                {
                    Console.WriteLine("Yes");
                    return;
                }
            }
        }
        Console.WriteLine("No");
    }
}
