directions = [(0, 1), (1, 0), (0, -1), (-1, 0)]

with open('mooyomooyo.in', 'r') as file:
    n, k = map(int, file.readline().split())
    board = []
    for i in range(n):
        row = file.readline().strip()
        board.append([int(j) for j in row])

v = len(board[0]) # v is the variable for columns

current_tiles = 0

def floodfill(row, col):
    global current_tiles
    current_tiles += 1
    value = board[row][col]
    visited[row][col] = True
    if current_tiles >= k:
        board[row][col] = 0
    for direction in directions:
        nrow, ncol = row+direction[0], col+direction[1] # new row, new col
        if nrow not in range(n):
            continue
        if ncol not in range(v):
            continue
        if value != board[nrow][ncol]:
            continue
        if visited[nrow][ncol] and current_tiles < k:
            continue
        floodfill(nrow, ncol)

def simulate_gravity():
    for j in range(v):
        column = [board[i][j] for i in range(n) if board[i][j] != 0]
        column = [0 for i in range(n-len(column))] + column
        for i in range(n):
            board[i][j] = column[i]

while True:
    deletion_occurred = False
    for i in range(n):
        for j in range(v):
            if board[i][j] != 0:
                current_tiles = 0
                visited = [[False for j in range(v)] for i in range(n)]
                floodfill(i, j)
                if current_tiles >= k:
                    deletion_occurred = True
    if deletion_occurred:
        simulate_gravity()
    else:
        break

with open('mooyomooyo.out', 'w') as file:
    for row in board:
        print(*row, sep='', file=file)