2x2_identical_squares_in_matrix

rows, cols = [int(n) for n in input().split()]

matrix = [input().split() for i in range(rows)]

identical_squares = 0

for i in range(rows - 1):
    for j in range(len(matrix[i])-1):
        current_symbol = matrix[i][j]
        if matrix[i][j+1] == current_symbol and matrix[i+1][j] == current_symbol and matrix[i+1][j+1] == current_symbol:
            identical_squares += 1

print(identical_squares)