/* 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
{
{
double x;
System.
out.
printf("\n Ответ " ); x=0;
int n;
Scanner in
= new Scanner
(System.
in); n = in.nextInt();
for(double i = 1; i <= n ; i++)
{
x += 1/ ((2 * i)*(2 * i)) ;
}
}
}
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