Adding Commas

Bessie is working with large numbers N (1 <= N <= 2,000,000,000) like 153920529 and realizes that the numbers would be a lot easier to read with commas inserted every three digits (as is normally done in the USA; some countries prefer to use periods every three digits). Thus, she would like to add commas: 153,920,529. Please write a program that does this.

• Line 1: A single integer: N

• Line 1: The integer N with commas inserted before each set of three digits except the first digits (as traditionally done in many cultures)