import re

def substitute(file_path):
    def replace(match):
        return ''.join(chr(ord('a') + int(digit)) for digit in match.group(0))

    with open(file_path, 'r', encoding='utf-8') as file:
        for line in file:
            substituted_line = re.sub(r'\b\d{4}\b', replace, line.strip())
            print(substituted_line)


file_path = 'TaskF00/simple.in'
substitute(file_path)