import java.util.Scanner;

class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt(),sum=0;
        double ave,tmpsum=0;
        while(n!=0){
            int [] s = new int[n];
            for(int i=0;i<n;i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            }
            ave = (double)sum/n;
            for(int i=0;i<n;i++) tmpsum += (s[i]-ave)*(s[i]-ave);
            ave = tmpsum/n;
            System.out.println(Math.sqrt(ave));
            sum = 0;
            tmpsum = 0;
            n = sc.nextInt();
        }
    }
} import java.util.Scanner; Scanner java.util class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt(),sum=0;
        double ave,tmpsum=0;
        while(n!=0){
            int [] s = new int[n];
            for(int i=0;i<n;i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            }
            ave = (double)sum/n;
            for(int i=0;i<n;i++) tmpsum += (s[i]-ave)*(s[i]-ave);
            ave = tmpsum/n;
            System.out.println(Math.sqrt(ave));
            sum = 0;
            tmpsum = 0;
            n = sc.nextInt();
        }
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt(),sum=0;
        double ave,tmpsum=0;
        while(n!=0){
            int [] s = new int[n];
            for(int i=0;i<n;i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            }
            ave = (double)sum/n;
            for(int i=0;i<n;i++) tmpsum += (s[i]-ave)*(s[i]-ave);
            ave = tmpsum/n;
            System.out.println(Math.sqrt(ave));
            sum = 0;
            tmpsum = 0;
            n = sc.nextInt();
        }
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt(),sum=0;
        double ave,tmpsum=0;
        while(n!=0){
            int [] s = new int[n];
            for(int i=0;i<n;i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            }
            ave = (double)sum/n;
            for(int i=0;i<n;i++) tmpsum += (s[i]-ave)*(s[i]-ave);
            ave = tmpsum/n;
            System.out.println(Math.sqrt(ave));
            sum = 0;
            tmpsum = 0;
            n = sc.nextInt();
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt() n sc.nextInt() sc.nextInt sc sum=0; sum 0 double ave ave tmpsum=0; tmpsum 0 while(n!=0){
            int [] s = new int[n];
            for(int i=0;i<n;i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            }
            ave = (double)sum/n;
            for(int i=0;i<n;i++) tmpsum += (s[i]-ave)*(s[i]-ave);
            ave = tmpsum/n;
            System.out.println(Math.sqrt(ave));
            sum = 0;
            tmpsum = 0;
            n = sc.nextInt();
        } n!=0 n 0 {
            int [] s = new int[n];
            for(int i=0;i<n;i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            }
            ave = (double)sum/n;
            for(int i=0;i<n;i++) tmpsum += (s[i]-ave)*(s[i]-ave);
            ave = tmpsum/n;
            System.out.println(Math.sqrt(ave));
            sum = 0;
            tmpsum = 0;
            n = sc.nextInt();
        } int [] s = new int[n]; s new int[n] n for(int i=0;i<n;i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            } int i=0; int i=0; i 0 i<n i n i++ i++ i {
                s[i] = sc.nextInt();
                sum += s[i];
            } {
                s[i] = sc.nextInt();
                sum += s[i];
            } s[i] = sc.nextInt() s[i] s i sc.nextInt() sc.nextInt sc sum += s[i] sum s[i] s i ave = (double)sum/n ave (double)sum/n (double)sum n for(int i=0;i<n;i++) tmpsum += (s[i]-ave)*(s[i]-ave); int i=0; int i=0; i 0 i<n i n i++ i++ i tmpsum += (s[i]-ave)*(s[i]-ave); tmpsum += (s[i]-ave)*(s[i]-ave) tmpsum (s[i]-ave)*(s[i]-ave) (s[i]-ave) s[i] s i ave (s[i]-ave) s[i] s i ave ave = tmpsum/n ave tmpsum/n tmpsum n System.out.println(Math.sqrt(ave)) System.out.println System.out System System.out Math.sqrt(ave) Math.sqrt Math ave sum = 0 sum 0 tmpsum = 0 tmpsum 0 n = sc.nextInt() n sc.nextInt() sc.nextInt sc String[] args args
import java.util.Scanner;

class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt(),sum=0;
        double ave,tmpsum=0;
        while(n!=0){
            int [] s = new int[n];
            for(int i=0;i<n;i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            }
            ave = (double)sum/n;
            for(int i=0;i<n;i++) tmpsum += (s[i]-ave)*(s[i]-ave);
            ave = tmpsum/n;
            System.out.println(Math.sqrt(ave));
            sum = 0;
            tmpsum = 0;
            n = sc.nextInt();
        }
    }
}
