import re


def make_strong_tags(line: str) -> str:
    """Find strong marks in string and replace them with <strong> tags."""
    return re.sub(
        r"""
            (?<![\w*_]) 
            (\*\*|__) 
            (?![<>\s\*_]) 
            ([^<>]+?) 
            (?<![<>\s*_]) 
            \1 
            (?![\w*_])
        """,
        r'<strong>\2</strong>',
        line,
        flags=re.X
    )