Problem:
Score : 200 points

Problem Statement

You are given an image A composed of N rows and N columns of pixels, and a template image B composed of M rows and M columns of pixels.

A pixel is the smallest element of an image, and in this problem it is a square of size 1×1.

Also, the given images are binary images, and the color of each pixel is either white or black.

In the input, every pixel is represented by a character: . corresponds to a white pixel, and # corresponds to a black pixel.

The image A is given as N strings A_1,...,A_N.

The j-th character in the string A_i corresponds to the pixel at the i-th row and j-th column of the image A (1≦i,j≦N).

Similarly, the template image B is given as M strings B_1,...,B_M.

The j-th character in the string B_i corresponds to the pixel at the i-th row and j-th column of the template image B (1≦i,j≦M).

Determine whether the template image B is contained in the image A when only parallel shifts can be applied to the images.

Constraints

1≦M≦N≦50

A_i is a string of length N consisting of # and ..

B_i is a string of length M consisting of # and ..

Input

The input is given from Standard Input in the following format:

N M
A_1
A_2
:
A_N
B_1
B_2
:
B_M

Output

Print Yes if the template image B is contained in the image A. Print No otherwise.

Sample Input 1

3 2
#.#
.#.
#.#
#.
.#

Sample Output 1

Yes

The template image B is identical to the upper-left 2 × 2 subimage and the lower-right 2 × 2 subimage of A. Thus, the output should be Yes.

Sample Input 2

4 1
....
....
....
....
#

Sample Output 2

No

The template image B, composed of a black pixel, is not contained in the image A composed of white pixels.

Solution in Ruby (2.3.3) (judge verdict: Wrong Answer)

#!/usr/bin/env ruby
# coding:utf-8

(n, m) = gets.chomp.split(' ')
n = n.to_i
m = m.to_i

a_array = Array.new
b_array = Array.new

n.times do
  line = gets.chomp
  a_array.push line
end


m.times do
  line = gets.chomp
  b_array.push line
end
ans = 'No'
for i in (0..(n - (m + 1)))
  offset = 0
  while (pos = (a_array[i].index(b_array[0], offset)))
#        puts "i: #{i} pos:#{pos}"
    (m - 1).times do |k|
#      puts "k: #{k}"
      if  ((i + k + 1) <= (n - 1)) && a_array[i + k + 1].slice(pos, m) != b_array[k + 1]
        offset = pos
        next
      end
      if k == (m - 2)
        ans = 'Yes'
        break
      end
    end
    offset = pos + 1
    if offset > n - 1
      next
    end
  end
end
puts ans