// 2023 IUSB Programming Competition
// Round 2 Problem 2
// Word Search
// Solution by Liguo Yu

import java.util.Scanner;

public class round2_p2
{   
    public static void main(String[] args)
    {
        Scanner input = new Scanner(System.in);
        String word = input.nextLine();

        int x = input.nextInt();
        int y = input.nextInt();
        char[][] array = new char[x][y];

        for (int i=0; i<x; i++)
        {
            for(int j=0; j<y; j++)
            {
                array[i][j] = input.next().charAt(0);
            }
        }
        
        boolean found = false;
        
        for (int i=0; i<x; i++)
        {
            for(int j=0; j<y; j++)
            {
                //for every position, check eight directions
                if(check(array, x, y, i, j, word) == true) found = true;
            }
        }
        
        if(found == false) System.out.println("no");
        else System.out.println("yes");
    }
     
    //for every position (m, n), check eight directions
    public static boolean check(char[][] array, int x, int y, int m, int n, String word)
    {
        //horizontally  forward
        String s = new String();
        for (int j=n; j<y; j++)
        {
            s = s + array[m][j];
        }
        if(s.contains(word)) return true;  
        
        //horizontally  backward
        s = new String();
        for (int j=n; j>=0; j--)
        {
            s = s + array[m][j];
        }          
        if(s.contains(word)) return true; 
               
        //vertically downward
        s = new String();
        for (int i=m; i<x; i++)
        {
            s = s + array[i][n];
        }
        if(s.contains(word)) return true;

        //vertically upward
        s = new String();
        for (int i=m; i>=0; i--)
        {
            s = s + array[i][n];
        }
        if(s.contains(word)) return true;
        
        // diagonally: /up
        s = new String();
        int i = m;
        int j = n;
        while(i >= 0 && j < y)
        {
            s = s + array[i][j];
            i--;
            j++;
        }
        if(s.contains(word)) return true;
        
        // diagonally: /down
        s = new String();
        i = m;
        j = n;
        while(i < x && j >= 0)
        {
            s = s + array[i][j];
            i++;
            j--;
        }
        if(s.contains(word)) return true;
        
        // diagonally: up
        s = new String();
        i = m;
        j = n;
        while(i >= 0 && j >= 0)
        {
            s = s + array[i][j];
            i--;
            j--;
        }
        if(s.contains(word)) return true;
        
        // diagonally: \down
        s = new String();
        i=m;
        j = n;
        while(i < x && j < y)
        {
            s = s + array[i][j];
            i++;
            j++;
        }
        if(s.contains(word)) return true;
        
        return false;
    }
    
}