I'm a newbie here and i can't solve this one

Tell us what’s happening:
Describe your issue in detail here.

   **Your code so far**

// Only change code below this line
var a;
var b;
var c;

a = 6;
var b = 15;
var c = "I am a String";

// Only change code above this line

a = a + 1; 
b = b + 5;
c = c + " String!";
   **Your browser information:**

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.63 Safari/537.36

Challenge: Understanding Uninitialized Variables

Link to the challenge:

You’ll need to assign the correct value as the instructions ask to each uninitialized variable. var a; // uninitialized variable with the value undefined
The bottom 3 lines should get the value the tests requires.
Here is what happens with the variable a

var a; // undefined
a = 6; // var a has value 6
a = a + 1; // var a has value 7

thank you so much for the helping me out :blush: