def add(x: int, y: int):
    """Add two numbers x and y
    >>> add(2, 3)
    5
    >>> add(5, 7)
    12
    """
    return x + y
from typing import List
def below_zero(operations: List[int]) -> bool:
    balance = 0
    for op in operations:
        balance += op
        if balance < 0:
            return True
    return False