import re

def replace(file_path):
    word_pattern = r'\b\w+\b'

    with open(file_path, 'r', encoding='utf-8') as file:
        for line in file:
            words = list(re.finditer(word_pattern, line))

            if len(words) >= 3:
                start, end = words[2].span()
                word_length = end - start
                line = line[:start] + 'x' * word_length + line[end:]
            
            print(line, end='')

file_path = 'TaskF05/simple.in'
replace(file_path)