First I put a security code to my phone.as it is nokia,when they ask code,i gave 12345.and then they ask me the new security code.then i gave 19714153 as the new one.then no changes have occured to my phone.and then i switched off my phone.when I on it,I went to security again and i gave the pin code.i donot know anything about these and I gave the same digits of security code in the same order.then suddenly my phone gets switched off and when I switch on it asks for PUK code.I do not know it.I attempt many times entering the incorrect code,as i donot know about this.what can i do?please give me sufficient response