import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);

        while(true){
            int num = scanner.nextInt();
            if (num == 0){
                break;
            }

            int[] score = new int[num];

            for(int i = 0; i < num; i++){
                score[i] = scanner.nextInt();
            }

            double ave;
            double sum = 0;
            for(int s : score){
                sum += s;
            }
            ave = sum / num;
            sum = 0;

            for(int s : score){
                sum += Math.pow(s-ave, 2);
            }

            System.out.println(Math.sqrt( sum / num));
        }

        scanner.close();
    }
}
 import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);

        while(true){
            int num = scanner.nextInt();
            if (num == 0){
                break;
            }

            int[] score = new int[num];

            for(int i = 0; i < num; i++){
                score[i] = scanner.nextInt();
            }

            double ave;
            double sum = 0;
            for(int s : score){
                sum += s;
            }
            ave = sum / num;
            sum = 0;

            for(int s : score){
                sum += Math.pow(s-ave, 2);
            }

            System.out.println(Math.sqrt( sum / num));
        }

        scanner.close();
    }
} Main public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);

        while(true){
            int num = scanner.nextInt();
            if (num == 0){
                break;
            }

            int[] score = new int[num];

            for(int i = 0; i < num; i++){
                score[i] = scanner.nextInt();
            }

            double ave;
            double sum = 0;
            for(int s : score){
                sum += s;
            }
            ave = sum / num;
            sum = 0;

            for(int s : score){
                sum += Math.pow(s-ave, 2);
            }

            System.out.println(Math.sqrt( sum / num));
        }

        scanner.close();
    } main {
        Scanner scanner = new Scanner(System.in);

        while(true){
            int num = scanner.nextInt();
            if (num == 0){
                break;
            }

            int[] score = new int[num];

            for(int i = 0; i < num; i++){
                score[i] = scanner.nextInt();
            }

            double ave;
            double sum = 0;
            for(int s : score){
                sum += s;
            }
            ave = sum / num;
            sum = 0;

            for(int s : score){
                sum += Math.pow(s-ave, 2);
            }

            System.out.println(Math.sqrt( sum / num));
        }

        scanner.close();
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) while(true){
            int num = scanner.nextInt();
            if (num == 0){
                break;
            }

            int[] score = new int[num];

            for(int i = 0; i < num; i++){
                score[i] = scanner.nextInt();
            }

            double ave;
            double sum = 0;
            for(int s : score){
                sum += s;
            }
            ave = sum / num;
            sum = 0;

            for(int s : score){
                sum += Math.pow(s-ave, 2);
            }

            System.out.println(Math.sqrt( sum / num));
        } true {
            int num = scanner.nextInt();
            if (num == 0){
                break;
            }

            int[] score = new int[num];

            for(int i = 0; i < num; i++){
                score[i] = scanner.nextInt();
            }

            double ave;
            double sum = 0;
            for(int s : score){
                sum += s;
            }
            ave = sum / num;
            sum = 0;

            for(int s : score){
                sum += Math.pow(s-ave, 2);
            }

            System.out.println(Math.sqrt( sum / num));
        } int num = scanner.nextInt(); num scanner.nextInt() scanner.nextInt scanner if (num == 0){
                break;
            } num == 0 num 0 {
                break;
            } break; int[] score = new int[num]; score new int[num] num for(int i = 0; i < num; i++){
                score[i] = scanner.nextInt();
            } int i = 0; int i = 0; i 0 i < num i num i++ i++ i {
                score[i] = scanner.nextInt();
            } {
                score[i] = scanner.nextInt();
            } score[i] = scanner.nextInt() score[i] score i scanner.nextInt() scanner.nextInt scanner double ave; ave double sum = 0; sum 0 for(int s : score){
                sum += s;
            } int s score {
                sum += s;
            } {
                sum += s;
            } sum += s sum s ave = sum / num ave sum / num sum num sum = 0 sum 0 for(int s : score){
                sum += Math.pow(s-ave, 2);
            } int s score {
                sum += Math.pow(s-ave, 2);
            } {
                sum += Math.pow(s-ave, 2);
            } sum += Math.pow(s-ave, 2) sum Math.pow(s-ave, 2) Math.pow Math s-ave s ave 2 System.out.println(Math.sqrt( sum / num)) System.out.println System.out System System.out Math.sqrt( sum / num) Math.sqrt Math sum / num sum num scanner.close() scanner.close scanner String[] args args public class Main {
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);

        while(true){
            int num = scanner.nextInt();
            if (num == 0){
                break;
            }

            int[] score = new int[num];

            for(int i = 0; i < num; i++){
                score[i] = scanner.nextInt();
            }

            double ave;
            double sum = 0;
            for(int s : score){
                sum += s;
            }
            ave = sum / num;
            sum = 0;

            for(int s : score){
                sum += Math.pow(s-ave, 2);
            }

            System.out.println(Math.sqrt( sum / num));
        }

        scanner.close();
    }
} public class Main {
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);

        while(true){
            int num = scanner.nextInt();
            if (num == 0){
                break;
            }

            int[] score = new int[num];

            for(int i = 0; i < num; i++){
                score[i] = scanner.nextInt();
            }

            double ave;
            double sum = 0;
            for(int s : score){
                sum += s;
            }
            ave = sum / num;
            sum = 0;

            for(int s : score){
                sum += Math.pow(s-ave, 2);
            }

            System.out.println(Math.sqrt( sum / num));
        }

        scanner.close();
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);

        while(true){
            int num = scanner.nextInt();
            if (num == 0){
                break;
            }

            int[] score = new int[num];

            for(int i = 0; i < num; i++){
                score[i] = scanner.nextInt();
            }

            double ave;
            double sum = 0;
            for(int s : score){
                sum += s;
            }
            ave = sum / num;
            sum = 0;

            for(int s : score){
                sum += Math.pow(s-ave, 2);
            }

            System.out.println(Math.sqrt( sum / num));
        }

        scanner.close();
    }
}

