"""
Illustrate how to add the integer without arithmetic operation
Author: suraj Kumar
Time Complexity: 1
https://en.wikipedia.org/wiki/Bitwise_operation
"""


def add(first: int, second: int) -> int:
    """
    Add two integers using bitwise operations instead of arithmetic operators.
    - XOR (^) to add bits without carrying
    - AND (&) to calculate carry bits
    - Left shift (<<) to move the carry to the correct position

    Examples:
    >>> add(3, 5)
    8
    >>> add(13, 5)
    18
    >>> add(-7, 2)
    -5
    >>> add(0, -7)
    -7
    >>> add(-321, 1)
    -320
    """

    while second != 0:  # Continue until there is no carry left
        c = first & second
        first ^= second
        second = c << 1
    return first


if __name__ == "__main__":
    import doctest

    doctest.testmod()

    first = int(input("Enter the first number: ").strip())
    second = int(input("Enter the second number: ").strip())
    print(f"{first = }, {second = }, {add(first, second) = }")