package main

import (
    "fmt"
    "strings"
    "strconv"
)
func main() {
    //a := 0
    //fmt.Scan(&a)
    //fmt.Printf("%d\n", a)
    s :=  "1e1.4.5.6"
    case1 := "2001:0db8:85a3:0:0:8A2E:0370:7334"
    case2 := "2001:0db8:85a3:0:0:8A2E:0370:7334:"
    res := IsIpv4OrIpv6(s)
    fmt.Println(res)
    res1 := IsIpv4OrIpv6(case1)
    fmt.Println(res1)
    res2 := IsIpv4OrIpv6(case2)
    fmt.Println(res2)
    fmt.Printf("Hello World!\n");
}

func IsIpv4OrIpv6(ip string) string{
    if len(ip)<7 {
        return "Neither"
    }
    arrIpv4 := strings.Split(ip,".")
    if len(arrIpv4) == 4{
        //. 判断IPv4
        for _,val := range arrIpv4{
            if !Judgev4(val){
                return "Neither"
            }
        }
        return "IPv4"
    }
    arrIpv6 := strings.Split(ip,":")
    if len(arrIpv6) == 8{
        // 判断Ipv6
        for _,val := range arrIpv6{
            if !Judgev6(val){
                return "Neither"
            }
        }
        return "IPv6"
    }
    return "Neither"
    
}
func Judgev4(ips string) bool{
    if len(ips) >3{
        return false
    }
    nums ,err := strconv.Atoi(ips)
    if err!= nil {
        return false
    }
    if nums <0 || nums>255{
        return false
    }
    if len(ips)>1 && ips[0] == '0'{
        return false
    }
    return true
}
func Judgev6(ips string) bool{
    if ips == ""{
        return true
    }
    if len(ips) >4{
        return  false
    }
    for _,val := range ips{
        if !((val>='0'&&val<='9')||(val >='a' &&val <= 'f')||(val >= 'A'&&val<='F')){
            return false
        }
    }
    return true
}