from pickle import TRUE
#
# 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可
#
# 验证IP地址
# @param IP string字符串 一个IP地址字符串
# @return string字符串
#
class Solution:
    def solve(self , IP: str) -> str:
        # write code here
        def is_ipv4(IP):
            parts = IP.split('.')
            if len(parts) != 4:
                return False
            for part in parts:
                if not part.isdigit():
                    return False
                if int(part) > 255 or int(part) < 0:
                    return False
                if int(part) > 0 and part.startswith('0'):
                    return False
            return TRUE
                 
        def is_ipv6(IP):
            parts = IP.split(':')
            if len(parts) != 8:
                return False
            for part in parts:
                if len(part) <1 or len(part) > 4:
                    return False
                try:
                    int(part,16)
                except:
                    return False
            return True
        if '.' in IP and is_ipv4(IP):
            return 'IPv4'
        elif ':' in IP and is_ipv6(IP):
            return 'IPv6'
        else:
            return 'Neither'