diff --git a/README.md b/README.md
index 1b40d5e..e491b67 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,37 @@
+## Filipac CNP - Validare CNP
 [![Build Status](https://travis-ci.org/filipac/cnp.svg)](https://travis-ci.org/laravel/framework)[![Latest Stable Version](https://poser.pugx.org/filipac/cnp/v/stable.svg)](https://packagist.org/packages/filipac/cnp) [![Total Downloads](https://poser.pugx.org/filipac/cnp/downloads.svg)](https://packagist.org/packages/filipac/cnp) [![Latest Unstable Version](https://poser.pugx.org/filipac/cnp/v/unstable.svg)](https://packagist.org/packages/filipac/cnp) [![License](https://poser.pugx.org/filipac/cnp/license.svg)](https://packagist.org/packages/filipac/cnp)
+
+### Cum instalez pachetul?
+```
+composer require filipac/cnp ~1.0
+```
+Sau introduceti in sectiunea require din ```composer.json```:
+```json
+"filipac/cnp": "~1.0"
+```
+
+### Cum folosesc acest pachet?
+Clasa ```Cnp``` are 2 metode publice statice: ```valid``` care returneaza un boolean (true, false). Este disponibila si functia
+```invalid``` care este practic functia valid, dar negata.
+```php
+<?php
+use Filipac\Cnp\Cnp;
+if(Cnp::valid('1930101021162')) #true
+	echo 'Cnp-ul este valid';
+if(! Cnp::valid('1930101021161')) #false
+   echo 'Cnp-ul este invalid';
+if(Cnp::invalid('1930101021161')) #true
+	echo 'Cnp-ul este invalid';
+if(!Cnp::invalid('1930101021162')) #false
+	echo 'Cnp-ul este valid';
+?>
+```
+
+### Cum sa contribui?
+Daca ai idei de imbunatatire a acestui script, da fork acestui repository, fa modificarile necesare si apoi da un pull-request.
+Nu uita sa scrii un test (vezi ```tests/CnpTest.php```) pentru ce ai implementat, altfel nu voi accepta request-ul.
+Testarea se face cu **PhpUnit**.
+
+### Licienta
+
+Acest script este distribuit sub [licienta MIT](http://opensource.org/licenses/MIT).
\ No newline at end of file
diff --git a/src/Cnp.php b/src/Cnp.php
index 30d33ca..1e1998d 100644
--- a/src/Cnp.php
+++ b/src/Cnp.php
@@ -4,6 +4,12 @@
 class Cnp
 {
 
+    public static function invalid($cnp)
+    {
+        return ! static::valid($cnp);
+    }
+
+
     public static function valid($p_cnp)
     {
         // CNP must have 13 characters
diff --git a/tests/CnpTest.php b/tests/CnpTest.php
index 7c61e3c..ae036ed 100644
--- a/tests/CnpTest.php
+++ b/tests/CnpTest.php
@@ -9,14 +9,20 @@ public function testCnpValid()
     {
         $valid = Cnp::valid('1930101021162');
         $this->assertTrue($valid);
+
+        $valid = Cnp::invalid('1930101021162');
+        $this->assertFalse($valid);
     }
 
 
     /** @test */
     public function testCnpInvalid()
     {
-        $valid = Cnp::valid('1930101021161');
-        $this->assertFalse($valid);
+        $invalid = Cnp::valid('1930101021161');
+        $this->assertFalse($invalid);
+
+        $invalid = Cnp::invalid('1930101021161');
+        $this->assertTrue($invalid);
     }
 
 }