import java.util.*;
import java.text.*;

class Main {
    public static void main(String[]args)throws Exception {
        Scanner sc = new Scanner(System.in);
        for(;;) {
            int n = sc.nextInt();
            if(n == 0) break;
            int [] xs = new int[n];
            long s = 0;
            for(int i = 0; i < n; i++) {
                xs[i] = sc.nextInt();
                s += xs[i];
            }
            double m = s / (double) n;
            double d = 0;
            for(int i = 0; i < n; i++) {
                d += (xs[i] - m) * (xs[i] - m);
            }
            d /= n;
            NumberFormat format = NumberFormat.getInstance();
            format.setMaximumFractionDigits(5);
            format.setMinimumFractionDigits(5);
            format.setGroupingUsed(false);
            System.out.println("" + format.format(Math.sqrt(d)));
        }
    }
} import java.util.*; util.* java import java.text.*; text.* java class Main {
    public static void main(String[]args)throws Exception {
        Scanner sc = new Scanner(System.in);
        for(;;) {
            int n = sc.nextInt();
            if(n == 0) break;
            int [] xs = new int[n];
            long s = 0;
            for(int i = 0; i < n; i++) {
                xs[i] = sc.nextInt();
                s += xs[i];
            }
            double m = s / (double) n;
            double d = 0;
            for(int i = 0; i < n; i++) {
                d += (xs[i] - m) * (xs[i] - m);
            }
            d /= n;
            NumberFormat format = NumberFormat.getInstance();
            format.setMaximumFractionDigits(5);
            format.setMinimumFractionDigits(5);
            format.setGroupingUsed(false);
            System.out.println("" + format.format(Math.sqrt(d)));
        }
    }
} Main public static void main(String[]args)throws Exception {
        Scanner sc = new Scanner(System.in);
        for(;;) {
            int n = sc.nextInt();
            if(n == 0) break;
            int [] xs = new int[n];
            long s = 0;
            for(int i = 0; i < n; i++) {
                xs[i] = sc.nextInt();
                s += xs[i];
            }
            double m = s / (double) n;
            double d = 0;
            for(int i = 0; i < n; i++) {
                d += (xs[i] - m) * (xs[i] - m);
            }
            d /= n;
            NumberFormat format = NumberFormat.getInstance();
            format.setMaximumFractionDigits(5);
            format.setMinimumFractionDigits(5);
            format.setGroupingUsed(false);
            System.out.println("" + format.format(Math.sqrt(d)));
        }
    } main {
        Scanner sc = new Scanner(System.in);
        for(;;) {
            int n = sc.nextInt();
            if(n == 0) break;
            int [] xs = new int[n];
            long s = 0;
            for(int i = 0; i < n; i++) {
                xs[i] = sc.nextInt();
                s += xs[i];
            }
            double m = s / (double) n;
            double d = 0;
            for(int i = 0; i < n; i++) {
                d += (xs[i] - m) * (xs[i] - m);
            }
            d /= n;
            NumberFormat format = NumberFormat.getInstance();
            format.setMaximumFractionDigits(5);
            format.setMinimumFractionDigits(5);
            format.setGroupingUsed(false);
            System.out.println("" + format.format(Math.sqrt(d)));
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) for(;;) {
            int n = sc.nextInt();
            if(n == 0) break;
            int [] xs = new int[n];
            long s = 0;
            for(int i = 0; i < n; i++) {
                xs[i] = sc.nextInt();
                s += xs[i];
            }
            double m = s / (double) n;
            double d = 0;
            for(int i = 0; i < n; i++) {
                d += (xs[i] - m) * (xs[i] - m);
            }
            d /= n;
            NumberFormat format = NumberFormat.getInstance();
            format.setMaximumFractionDigits(5);
            format.setMinimumFractionDigits(5);
            format.setGroupingUsed(false);
            System.out.println("" + format.format(Math.sqrt(d)));
        } ; {
            int n = sc.nextInt();
            if(n == 0) break;
            int [] xs = new int[n];
            long s = 0;
            for(int i = 0; i < n; i++) {
                xs[i] = sc.nextInt();
                s += xs[i];
            }
            double m = s / (double) n;
            double d = 0;
            for(int i = 0; i < n; i++) {
                d += (xs[i] - m) * (xs[i] - m);
            }
            d /= n;
            NumberFormat format = NumberFormat.getInstance();
            format.setMaximumFractionDigits(5);
            format.setMinimumFractionDigits(5);
            format.setGroupingUsed(false);
            System.out.println("" + format.format(Math.sqrt(d)));
        } {
            int n = sc.nextInt();
            if(n == 0) break;
            int [] xs = new int[n];
            long s = 0;
            for(int i = 0; i < n; i++) {
                xs[i] = sc.nextInt();
                s += xs[i];
            }
            double m = s / (double) n;
            double d = 0;
            for(int i = 0; i < n; i++) {
                d += (xs[i] - m) * (xs[i] - m);
            }
            d /= n;
            NumberFormat format = NumberFormat.getInstance();
            format.setMaximumFractionDigits(5);
            format.setMinimumFractionDigits(5);
            format.setGroupingUsed(false);
            System.out.println("" + format.format(Math.sqrt(d)));
        } int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc if(n == 0) break; n == 0 n 0 break; int [] xs = new int[n]; xs new int[n] n long s = 0; s 0 for(int i = 0; i < n; i++) {
                xs[i] = sc.nextInt();
                s += xs[i];
            } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
                xs[i] = sc.nextInt();
                s += xs[i];
            } {
                xs[i] = sc.nextInt();
                s += xs[i];
            } xs[i] = sc.nextInt() xs[i] xs i sc.nextInt() sc.nextInt sc s += xs[i] s xs[i] xs i double m = s / (double) n; m s / (double) n s (double) n double d = 0; d 0 for(int i = 0; i < n; i++) {
                d += (xs[i] - m) * (xs[i] - m);
            } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
                d += (xs[i] - m) * (xs[i] - m);
            } {
                d += (xs[i] - m) * (xs[i] - m);
            } d += (xs[i] - m) * (xs[i] - m) d (xs[i] - m) * (xs[i] - m) (xs[i] - m) xs[i] xs i m (xs[i] - m) xs[i] xs i m d /= n d n NumberFormat format = NumberFormat.getInstance(); format NumberFormat.getInstance() NumberFormat.getInstance NumberFormat format.setMaximumFractionDigits(5) format.setMaximumFractionDigits format 5 format.setMinimumFractionDigits(5) format.setMinimumFractionDigits format 5 format.setGroupingUsed(false) format.setGroupingUsed format false System.out.println("" + format.format(Math.sqrt(d))) System.out.println System.out System System.out "" + format.format(Math.sqrt(d)) "" format.format(Math.sqrt(d)) format.format format Math.sqrt(d) Math.sqrt Math d String[]args args
import java.util.*;
import java.text.*;

class Main {
    public static void main(String[]args)throws Exception {
        Scanner sc = new Scanner(System.in);
        for(;;) {
            int n = sc.nextInt();
            if(n == 0) break;
            int [] xs = new int[n];
            long s = 0;
            for(int i = 0; i < n; i++) {
                xs[i] = sc.nextInt();
                s += xs[i];
            }
            double m = s / (double) n;
            double d = 0;
            for(int i = 0; i < n; i++) {
                d += (xs[i] - m) * (xs[i] - m);
            }
            d /= n;
            NumberFormat format = NumberFormat.getInstance();
            format.setMaximumFractionDigits(5);
            format.setMinimumFractionDigits(5);
            format.setGroupingUsed(false);
            System.out.println("" + format.format(Math.sqrt(d)));
        }
    }
}