Write a program that reads four integers and determines if two of them are equal and the remaining ones are different from any other.
Input
Four integers in one line.
Output
If two integers in the input are equal to each other and the other two are different from any other one then print YES. Otherwise, print NO.
Observation
You cannot use massive storage data structures, such as string or vector.
Input
15 -30 2 15
Output
YES
Input
-333 22 -333 -333
Output
NO
Input
0 0 0 0
Output
NO
Input
1 2 4 8
Output
NO
Input
1 -1 1 -1
Output
NO