cho.sh

No Duplicates

Read a line of space-separated uppercase words and print yes if no word repeats, or no if any word appears more than once.

Easy2StringHash mapImplementationInterviewNo attempts yetTime limit2sMemory limit512 MB

Problem

There is a game in which one player tries not to repeat a word while the other player tries to catch a repeat.

"THE RAIN IN SPAIN" has no repeats.

"IN THE RAIN AND THE SNOW" repeats THE.

"THE RAIN IN SPAIN IN THE PLAIN" repeats THE and IN.

Write a program that tests a phrase.

Input

The first line contains words separated by single spaces. Each word is one or more uppercase letters. The line is at most 80 characters long.

Output

Print yes if no word is repeated, and no if one or more words repeat.