/* 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
{
public static void main
(String[] args
) { Scanner in
= new Scanner
(System.
in); int n = in.nextInt();
int[] arr = new int[n];
double sum = 0.0;
for(int i = 0; i < n; i++) {
arr[i] = in.nextInt();
}
double mean = 0;
for(int i = 0; i < n; i++) {
mean += arr[i];
}
mean /= n;
for(int i = 0; i < n; i++) {
sum
+= Math.
pow(arr
[i
] - mean,
2); }
}
}
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