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Problems

Parallelogram

Parallelogram

4 numbers a, b, c, d, defining lengths of pieces are set. Define, is it possible to form a parallelogram from these pieces.

Input

In a unique line set 4 numbers through a blank.

Output

Deduce in a unique line a word "YES" if it is possible to form a parallelogram or "NO" (without inverted commas) otherwise.

Time limit 0.5 seconds
Memory limit 64 MiB
Input example #1
2 4 2 4
Output example #1
YES
Source SFE-2010 Variant 29