Openjudge: find the first character that appears only once

describe

Given a string containing only lowercase letters , Please find the first character that appears only once . without , Output no.

Input

A string , The length is less than 100000.

Output

Output the first character that appears only once , If not, output no.

Instance input

abcabd

Instance output

c

Code

while True:
    try:
        a = input().strip()
        for i in a:
            if a.count(i) == 1:
                print(i)
                exit(0)
        else:
            print('no')
    except:
        break