Daily Coding - DAY 1 # typographically smallest

Given a string consisting of lowercase letters only, find the typographically smallest string not present as a substring in it.

Given two string S1 and S2. S1 is considered typographically smaller than S2 if either:

Input:

The first line of input contains the string S.

Output:

Answer as stated above.

Constraints:

Sample Input

saurabh

Sample Output

c

Comments

[DINESH]

This is from a ongoing contest.Try yourself dont ask for help without trying