String Compression

Given a string s, your task is to compress it by replacing every group of consecutive identical characters with the character followed by the number of occurrences. For example:

Input: aaabbbcccc
Output: a3b3c4

If a character appears only once, it should still be followed by 1. For instance:

Input: abcd
Output: a1b1c1d1

This problem requires you to perform run-length encoding on the input string.

inputFormat

The input is provided via standard input (stdin) as a single line containing the string s to be compressed.

Constraints: The string can consist of uppercase and lowercase letters. The length of the string is at least 1 and can be reasonably large.

outputFormat

Output the compressed version of the string to standard output (stdout).

aaabbbcccc

a3b3c4