/* 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();
    }
    Arrays.sort(arr);
    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);
    }
    System.out.printf("%.1f", Math.sqrt(sum/n));
 }
}

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

MTAKCjY0NjMwIDExNzM1IDE0MjE2IDk5MjMzIDE0NDcwIDQ5NzggNzM0MjkgMzgxMjAgNTExMzUgNjcwNjA=

10

64630 11735 14216 99233 14470 4978 73429 38120 51135 67060