
    Design a function for the bank's transaction monitoring system that identifies the leading digit of any transaction amount to enable rapid risk categorization. The system needs to process whole-number transaction amounts and extract only the leftmost digit, which serves as an initial indicator for transaction magnitude classification.
    

    
def first_Digit(n):
    """
    Design a function for the bank's transaction monitoring system that identifies the leading digit of any transaction amount to enable rapid risk categorization. The system needs to process whole-number transaction amounts and extract only the leftmost digit, which serves as an initial indicator for transaction magnitude classification.
    

    """
def first_Digit(n):
    """
    Design a function for the bank's transaction monitoring system that identifies the leading digit of any transaction amount to enable rapid risk categorization. The system needs to process whole-number transaction amounts and extract only the leftmost digit, which serves as an initial indicator for transaction magnitude classification.
    

    """
    while n >= 10:
        n = n / 10
    return int(n)