import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        List<Integer> score = new ArrayList<>();
        double total = 0;
        double a2n = 0.0;
        while(true){
        int n = sc.nextInt();
        if(n == 0){
            break;
        }
        for(int i = 0; i < n; i++){
            int s = sc.nextInt();
            score.add(s);
            total += s;
        }
        for(int i:score){
           a2n += Math.pow(i - (total/n), 2);
        }
        System.out.println(Math.sqrt(a2n/n));
        total = 0;
        a2n = 0;
        score.clear();
        }
                }
} import java.util.ArrayList; ArrayList java.util import java.util.List; List java.util import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        List<Integer> score = new ArrayList<>();
        double total = 0;
        double a2n = 0.0;
        while(true){
        int n = sc.nextInt();
        if(n == 0){
            break;
        }
        for(int i = 0; i < n; i++){
            int s = sc.nextInt();
            score.add(s);
            total += s;
        }
        for(int i:score){
           a2n += Math.pow(i - (total/n), 2);
        }
        System.out.println(Math.sqrt(a2n/n));
        total = 0;
        a2n = 0;
        score.clear();
        }
                }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        List<Integer> score = new ArrayList<>();
        double total = 0;
        double a2n = 0.0;
        while(true){
        int n = sc.nextInt();
        if(n == 0){
            break;
        }
        for(int i = 0; i < n; i++){
            int s = sc.nextInt();
            score.add(s);
            total += s;
        }
        for(int i:score){
           a2n += Math.pow(i - (total/n), 2);
        }
        System.out.println(Math.sqrt(a2n/n));
        total = 0;
        a2n = 0;
        score.clear();
        }
                } main {
        Scanner sc = new Scanner(System.in);
        List<Integer> score = new ArrayList<>();
        double total = 0;
        double a2n = 0.0;
        while(true){
        int n = sc.nextInt();
        if(n == 0){
            break;
        }
        for(int i = 0; i < n; i++){
            int s = sc.nextInt();
            score.add(s);
            total += s;
        }
        for(int i:score){
           a2n += Math.pow(i - (total/n), 2);
        }
        System.out.println(Math.sqrt(a2n/n));
        total = 0;
        a2n = 0;
        score.clear();
        }
                } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) List<Integer> score = new ArrayList<>(); score new ArrayList<>() double total = 0; total 0 double a2n = 0.0; a2n 0.0 while(true){
        int n = sc.nextInt();
        if(n == 0){
            break;
        }
        for(int i = 0; i < n; i++){
            int s = sc.nextInt();
            score.add(s);
            total += s;
        }
        for(int i:score){
           a2n += Math.pow(i - (total/n), 2);
        }
        System.out.println(Math.sqrt(a2n/n));
        total = 0;
        a2n = 0;
        score.clear();
        } true {
        int n = sc.nextInt();
        if(n == 0){
            break;
        }
        for(int i = 0; i < n; i++){
            int s = sc.nextInt();
            score.add(s);
            total += s;
        }
        for(int i:score){
           a2n += Math.pow(i - (total/n), 2);
        }
        System.out.println(Math.sqrt(a2n/n));
        total = 0;
        a2n = 0;
        score.clear();
        } int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc if(n == 0){
            break;
        } n == 0 n 0 {
            break;
        } break; for(int i = 0; i < n; i++){
            int s = sc.nextInt();
            score.add(s);
            total += s;
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            int s = sc.nextInt();
            score.add(s);
            total += s;
        } {
            int s = sc.nextInt();
            score.add(s);
            total += s;
        } int s = sc.nextInt(); s sc.nextInt() sc.nextInt sc score.add(s) score.add score s total += s total s for(int i:score){
           a2n += Math.pow(i - (total/n), 2);
        } int i score {
           a2n += Math.pow(i - (total/n), 2);
        } {
           a2n += Math.pow(i - (total/n), 2);
        } a2n += Math.pow(i - (total/n), 2) a2n Math.pow(i - (total/n), 2) Math.pow Math i - (total/n) i (total/n) total n 2 System.out.println(Math.sqrt(a2n/n)) System.out.println System.out System System.out Math.sqrt(a2n/n) Math.sqrt Math a2n/n a2n n total = 0 total 0 a2n = 0 a2n 0 score.clear() score.clear score String[] args args public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        List<Integer> score = new ArrayList<>();
        double total = 0;
        double a2n = 0.0;
        while(true){
        int n = sc.nextInt();
        if(n == 0){
            break;
        }
        for(int i = 0; i < n; i++){
            int s = sc.nextInt();
            score.add(s);
            total += s;
        }
        for(int i:score){
           a2n += Math.pow(i - (total/n), 2);
        }
        System.out.println(Math.sqrt(a2n/n));
        total = 0;
        a2n = 0;
        score.clear();
        }
                }
} public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        List<Integer> score = new ArrayList<>();
        double total = 0;
        double a2n = 0.0;
        while(true){
        int n = sc.nextInt();
        if(n == 0){
            break;
        }
        for(int i = 0; i < n; i++){
            int s = sc.nextInt();
            score.add(s);
            total += s;
        }
        for(int i:score){
           a2n += Math.pow(i - (total/n), 2);
        }
        System.out.println(Math.sqrt(a2n/n));
        total = 0;
        a2n = 0;
        score.clear();
        }
                }
} Main
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        List<Integer> score = new ArrayList<>();
        double total = 0;
        double a2n = 0.0;
        while(true){
        int n = sc.nextInt();
        if(n == 0){
            break;
        }
        for(int i = 0; i < n; i++){
            int s = sc.nextInt();
            score.add(s);
            total += s;
        }
        for(int i:score){
           a2n += Math.pow(i - (total/n), 2);
        }
        System.out.println(Math.sqrt(a2n/n));
        total = 0;
        a2n = 0;
        score.clear();
        }
                }
}