/* package whatever; // don't place package name! */
import java.util.*;
import java.lang.*;
import java.io.*;
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
{
System.
out.
println(x
(100,
5)); }
public static int x(int n, int p)
{
return -((p%2<1) ? p*p/2+p : p/2 * (p+2) + 1) + n - p*n;
}
}
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