Problem

At Meta, systems such as network-facing services and internal traffic filters need strict IP parsing. Implement a function that takes a string and returns whether it is a valid IPv4 address, valid IPv6 address, or Neither.

Formal Specification

Write a function validate_ip(address) that accepts a string address and returns one of:

• "IPv4" if the string is a valid IPv4 address
• "IPv6" if the string is a valid IPv6 address
• "Neither" otherwise

A valid IPv4 address has exactly 4 decimal parts separated by .. Each part must contain only digits, be in the range 0 to 255, and must not contain leading zeros unless the part is exactly "0".

A valid IPv6 address has exactly 8 parts separated by :. Each part must be 1 to 4 characters long and contain only hexadecimal characters: 0-9, a-f, or A-F.

Examples

Example 1

• Input: address = "172.16.254.1"
• Output: "IPv4"
• Explanation: The string has 4 decimal segments, each within 0..255, and no invalid leading zeros.

Example 2

• Input: address = "2001:0db8:85a3:0:0:8A2E:0370:7334"
• Output: "IPv6"
• Explanation: The string has 8 valid hexadecimal groups, each 1 to 4 characters long.

Constraints

• 1 <= len(address) <= 100
• Input may contain letters, digits, ., :, or other ASCII characters
• Do not use built-in IP parsing libraries