def check_row_winner(input_list, size):
    """
    Check the winner number in row direction.

    Arguments:
    input_list -- a two dimensional list for checking.
    size -- the length for winning.
    
    Returns:
    winner -- the winner player number, if no winner return None.
    
    """
    for line in input_list:
        count = 1
        for idx, value in enumerate(line):
            if line[idx] == line[idx+1]:
                count += 1
            else:
                count = 1
            if count == size and value != 0:
                return value
            if idx == len(line)-size+1:
                break