#!/usr/bin/env python3
"""Count Python files in directory tree recursively."""
import sys
from pathlib import Path

def count_py_files(directory: str = ".") -> int:
    """Count Python files in directory tree."""
    return len(list(Path(directory).rglob("*.py")))

if __name__ == "__main__":
    target = sys.argv[1] if len(sys.argv) > 1 else "."
    print(count_py_files(target))