
    Write a function that extracts the first digit from a delivery route's identifier number to determine its primary service zone, where each zone is represented by the leading digit of the route number. The function should process any valid route identifier and return its first digit, which is crucial for initial route classification and zone-based dispatch decisions.
    

    
def first_Digit(n):
    """
    Write a function that extracts the first digit from a delivery route's identifier number to determine its primary service zone, where each zone is represented by the leading digit of the route number. The function should process any valid route identifier and return its first digit, which is crucial for initial route classification and zone-based dispatch decisions.
    

    """
def first_Digit(n):
    """
    Write a function that extracts the first digit from a delivery route's identifier number to determine its primary service zone, where each zone is represented by the leading digit of the route number. The function should process any valid route identifier and return its first digit, which is crucial for initial route classification and zone-based dispatch decisions.
    

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