import java.util.Scanner;

class Main {
    public static void main(String[] args) {
        int n, sum;
        int[] s;
        double dev;
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        while (n != 0) {
            s = new int [n];
            sum = 0;
            for (int i = 0; i < n; i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            }
            dev = 0;
            for (int i = 0; i < n; i++) 
                dev += (s[i] - ((double)sum / n)) * ((double)s[i] - (sum / n));
            System.out.printf("%.9f\n", Math.sqrt(dev / n));
            n = sc.nextInt();
        }
    }
} import java.util.Scanner; Scanner java.util class Main {
    public static void main(String[] args) {
        int n, sum;
        int[] s;
        double dev;
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        while (n != 0) {
            s = new int [n];
            sum = 0;
            for (int i = 0; i < n; i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            }
            dev = 0;
            for (int i = 0; i < n; i++) 
                dev += (s[i] - ((double)sum / n)) * ((double)s[i] - (sum / n));
            System.out.printf("%.9f\n", Math.sqrt(dev / n));
            n = sc.nextInt();
        }
    }
} Main public static void main(String[] args) {
        int n, sum;
        int[] s;
        double dev;
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        while (n != 0) {
            s = new int [n];
            sum = 0;
            for (int i = 0; i < n; i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            }
            dev = 0;
            for (int i = 0; i < n; i++) 
                dev += (s[i] - ((double)sum / n)) * ((double)s[i] - (sum / n));
            System.out.printf("%.9f\n", Math.sqrt(dev / n));
            n = sc.nextInt();
        }
    } main {
        int n, sum;
        int[] s;
        double dev;
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        while (n != 0) {
            s = new int [n];
            sum = 0;
            for (int i = 0; i < n; i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            }
            dev = 0;
            for (int i = 0; i < n; i++) 
                dev += (s[i] - ((double)sum / n)) * ((double)s[i] - (sum / n));
            System.out.printf("%.9f\n", Math.sqrt(dev / n));
            n = sc.nextInt();
        }
    } int n n sum; sum int[] s; s double dev; dev Scanner sc = new Scanner(System.in); sc new Scanner(System.in) n = sc.nextInt() n sc.nextInt() sc.nextInt sc while (n != 0) {
            s = new int [n];
            sum = 0;
            for (int i = 0; i < n; i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            }
            dev = 0;
            for (int i = 0; i < n; i++) 
                dev += (s[i] - ((double)sum / n)) * ((double)s[i] - (sum / n));
            System.out.printf("%.9f\n", Math.sqrt(dev / n));
            n = sc.nextInt();
        } n != 0 n 0 {
            s = new int [n];
            sum = 0;
            for (int i = 0; i < n; i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            }
            dev = 0;
            for (int i = 0; i < n; i++) 
                dev += (s[i] - ((double)sum / n)) * ((double)s[i] - (sum / n));
            System.out.printf("%.9f\n", Math.sqrt(dev / n));
            n = sc.nextInt();
        } s = new int [n] s new int [n] n sum = 0 sum 0 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 dev = 0 dev 0 for (int i = 0; i < n; i++) 
                dev += (s[i] - ((double)sum / n)) * ((double)s[i] - (sum / n)); int i = 0; int i = 0; i 0 i < n i n i++ i++ i dev += (s[i] - ((double)sum / n)) * ((double)s[i] - (sum / n)); dev += (s[i] - ((double)sum / n)) * ((double)s[i] - (sum / n)) dev (s[i] - ((double)sum / n)) * ((double)s[i] - (sum / n)) (s[i] - ((double)sum / n)) s[i] s i ((double)sum / n) (double)sum n ((double)s[i] - (sum / n)) (double)s[i] s i (sum / n) sum n System.out.printf("%.9f\n", Math.sqrt(dev / n)) System.out.printf System.out System System.out "%.9f\n" Math.sqrt(dev / n) Math.sqrt Math dev / n dev n n = sc.nextInt() n sc.nextInt() sc.nextInt sc String[] args args
import java.util.Scanner;

class Main {
    public static void main(String[] args) {
        int n, sum;
        int[] s;
        double dev;
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        while (n != 0) {
            s = new int [n];
            sum = 0;
            for (int i = 0; i < n; i++) {
                s[i] = sc.nextInt();
                sum += s[i];
            }
            dev = 0;
            for (int i = 0; i < n; i++) 
                dev += (s[i] - ((double)sum / n)) * ((double)s[i] - (sum / n));
            System.out.printf("%.9f\n", Math.sqrt(dev / n));
            n = sc.nextInt();
        }
    }
}
