Task
Time limit: 1000 ms,
Memory limit: 256 Mb

At the next chess competition posted a starting list. During the discussion of the start list, it was superstition that a three-digit number consisting of the same numbers is lucky. Write a program that determines whether he is happy or not by a three-digit number.
Input: one three-digit number \(n\ (100<=n<=999)\) is input to the program
Output: output YES, if the number is lucky, otherwise output NO

Example 1
Input
111
Output
YES

Example 2
Input
112
Output
NO
Prohibited statements:while;for;do;until