Given four integer values, determine if one of them is equal to the mean of other two values.
Remember that the mean of two values $a$ and $b$ is $\frac{a + b}{2}$.
Input
The first line of the input contains the four integers $a$, $b$, $c$ and $d$ ($1 \le a, b, c, d \le 100$).
Output
If there exists one value that is equal to the mean of the other two values, then print "Yes" without quotes, otherwise print "No" without quotes.
Sample test(s)
Input
3 10 1 2
Output
YES
Input
100 100 100 100
Output
YES
Input
10 21 21 15
Output
NO