Book Worm 2

#!usr/local/bin/python3.8
# -*- coding: utf-8 -*import


def find_player(m: list):
    """
    Find the initial position of the player.
    :param m:
    :return: x: int, y: int
    """
    for x in range(matrix_size):
        for y in range(len(m[x])):
            if m[x][y] == 'P':
                return x, y


def is_valid(i: int):
    return 0 <= i < matrix_size


def up(x: int, y: int):
    return x - 1, y


def down(x: int, y: int):
    return x + 1, y


def left(x: int, y: int):
    return x, y - 1


def right(x: int, y: int):
    return x, y + 1


def manage(x: str):
    global matrix, player_row, player_col, text, MOVES
    new_row, new_col = MOVES[x](player_row, player_col)
    if not is_valid(new_row) or not is_valid(new_col):
        if text:
            text = text[:-1]
    else:
        cell = matrix[new_row][new_col]
        if cell != '-':
            text += matrix[new_row][new_col]
            matrix[new_row][new_col] = 'P'
            matrix[player_row][player_col] = '-'
            player_row, player_col = new_row, new_col
        else:
            matrix[new_row][new_col] = 'P'
            matrix[player_row][player_col] = '-'
            player_row, player_col = new_row, new_col


MOVES = {
    'up': up,
    'down': down,
    'left': left,
    'right': right,
}

text = input()
matrix_size = int(input())
matrix = [list(input()) for _ in range(matrix_size)]
player_row, player_col = find_player(matrix)

while True:
    move = input()
    if move == 'end':
        break
    manage(move)

if text:
    print(text)
[print(''.join(x)) for x in matrix]