Simple decryption

Problem Statement

You come across a dump of secrets that have a very simple eneryption. Each secret is a simple string that contains combination of $10$ or less than $10$ unique letters from a to $z_1$ without any spaces or special characters.

The encryption scheme is as follows:

In the final encrypted string, each unique letter appears only once, For each subsequent appearance of the letter, it is denoted by the letter's index in the list of unique letters in the string, ordered by its first appearance.

For example if the secret string is doctorstrange, the encrypted string will be doct$1$rs$34$ange

For a given encrypted string str$,$ you need to crack the code and figure out the original unencrypted string.

Input Format

Input contains a single string str$.$

Constraints

$1\mathrm{.}1s=$ length$($str$){10}^{{?}^{?}}7-1$

$2.$ Total number of unique characters in str will be $10$

Output Format

A single string which is the unencrypted version of encrypted string str$.$ If the encrypted string is invalid, i$.$e$.$ it cannot be a valid encrypted string as per the above encryption schema, the output should be "invalid code"

Sample Input:

doct$1$rs$34$ange

Sample Output:

doctorstrange

$\backslash$table$[[$Letter$,$Untque Characters List,CharacteriDiglt,Unenerypted String$],[$d$,[$d$],$character,d$],[,d,0,$character,$],[$c$,d,0,d,$character,c$],[$t$,d,0,c,t,$character,t$],[1,d,0,c,t,$digit,$-],[r,d,0,c,t,r,$character,$r$