//Write a program to Validate an IPv4 Address.
#include<iostream>
#include<string>
using namespace std;

bool isDigit(char ch)
{
    return ((ch>='0') && (ch<='9'))?true:false;
}

bool function(string str)
{
    int temp = 0, dots = 0, i = 0;
    int len = str.length();
    while(i<len)
    {
        if(!i && str[i] == '.')
            return false;
        else if(i>0 && str[i] == '.' && str[i-1] == '.')
            return false;
        else if(str[i] == '.')
        {
            dots++;
            i++;
            if((dots>3) || (i==len))
                return false;
            temp = 0;
            continue;
        }
        else if(str[i] != '.' && !isDigit(str[i]))
            return false;
        temp = temp*10 + str[i]-'0';
        if(temp>255 || dots>3)
            return false;
        i++;
        if(i==len && dots<3)
            return false;
    }
}

int main()
{
    string str;
    cout<<"  Enter string :- ";
    cin>>str;
    cout<<(function(str)?" Valid ":" Invalid ")<<endl;
    system("PAUSE");
    return 0;
}