import java.util.Scanner;

public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int i, j, k;
        double a, b, m, n;
        double[] Score = new double[10000];
        for(i = 0; ; i++){
            int Total = 0;
            double Totalup = 0.0;
            n = sc.nextDouble();
            if(n == 0.0){
                break;
            } else{
                for(j = 0; j < n; j++){
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                }
                m = Total / n;
            }
            for(k = 0; k < n; k++){
                Totalup += Math.pow(Score[k] - m, 2.0);
            }
            a = Totalup / n;
            b = Math.pow(a, 0.5);
            System.out.println(b);
        }
    }
} import java.util.Scanner; Scanner java.util public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int i, j, k;
        double a, b, m, n;
        double[] Score = new double[10000];
        for(i = 0; ; i++){
            int Total = 0;
            double Totalup = 0.0;
            n = sc.nextDouble();
            if(n == 0.0){
                break;
            } else{
                for(j = 0; j < n; j++){
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                }
                m = Total / n;
            }
            for(k = 0; k < n; k++){
                Totalup += Math.pow(Score[k] - m, 2.0);
            }
            a = Totalup / n;
            b = Math.pow(a, 0.5);
            System.out.println(b);
        }
    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int i, j, k;
        double a, b, m, n;
        double[] Score = new double[10000];
        for(i = 0; ; i++){
            int Total = 0;
            double Totalup = 0.0;
            n = sc.nextDouble();
            if(n == 0.0){
                break;
            } else{
                for(j = 0; j < n; j++){
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                }
                m = Total / n;
            }
            for(k = 0; k < n; k++){
                Totalup += Math.pow(Score[k] - m, 2.0);
            }
            a = Totalup / n;
            b = Math.pow(a, 0.5);
            System.out.println(b);
        }
    } main {
        Scanner sc = new Scanner(System.in);
        int i, j, k;
        double a, b, m, n;
        double[] Score = new double[10000];
        for(i = 0; ; i++){
            int Total = 0;
            double Totalup = 0.0;
            n = sc.nextDouble();
            if(n == 0.0){
                break;
            } else{
                for(j = 0; j < n; j++){
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                }
                m = Total / n;
            }
            for(k = 0; k < n; k++){
                Totalup += Math.pow(Score[k] - m, 2.0);
            }
            a = Totalup / n;
            b = Math.pow(a, 0.5);
            System.out.println(b);
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int i i j j k; k double a a b b m m n; n double[] Score = new double[10000]; Score new double[10000] 10000 for(i = 0; ; i++){
            int Total = 0;
            double Totalup = 0.0;
            n = sc.nextDouble();
            if(n == 0.0){
                break;
            } else{
                for(j = 0; j < n; j++){
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                }
                m = Total / n;
            }
            for(k = 0; k < n; k++){
                Totalup += Math.pow(Score[k] - m, 2.0);
            }
            a = Totalup / n;
            b = Math.pow(a, 0.5);
            System.out.println(b);
        } i = 0; i = 0 i 0 i++ i++ i {
            int Total = 0;
            double Totalup = 0.0;
            n = sc.nextDouble();
            if(n == 0.0){
                break;
            } else{
                for(j = 0; j < n; j++){
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                }
                m = Total / n;
            }
            for(k = 0; k < n; k++){
                Totalup += Math.pow(Score[k] - m, 2.0);
            }
            a = Totalup / n;
            b = Math.pow(a, 0.5);
            System.out.println(b);
        } {
            int Total = 0;
            double Totalup = 0.0;
            n = sc.nextDouble();
            if(n == 0.0){
                break;
            } else{
                for(j = 0; j < n; j++){
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                }
                m = Total / n;
            }
            for(k = 0; k < n; k++){
                Totalup += Math.pow(Score[k] - m, 2.0);
            }
            a = Totalup / n;
            b = Math.pow(a, 0.5);
            System.out.println(b);
        } int Total = 0; Total 0 double Totalup = 0.0; Totalup 0.0 n = sc.nextDouble() n sc.nextDouble() sc.nextDouble sc if(n == 0.0){
                break;
            } else{
                for(j = 0; j < n; j++){
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                }
                m = Total / n;
            } n == 0.0 n 0.0 {
                break;
            } break; {
                for(j = 0; j < n; j++){
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                }
                m = Total / n;
            } for(j = 0; j < n; j++){
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                } j = 0; j = 0 j 0 j < n j n j++ j++ j {
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                } {
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                } Score[j] = sc.nextDouble() Score[j] Score j sc.nextDouble() sc.nextDouble sc Total += Score[j] Total Score[j] Score j m = Total / n m Total / n Total n for(k = 0; k < n; k++){
                Totalup += Math.pow(Score[k] - m, 2.0);
            } k = 0; k = 0 k 0 k < n k n k++ k++ k {
                Totalup += Math.pow(Score[k] - m, 2.0);
            } {
                Totalup += Math.pow(Score[k] - m, 2.0);
            } Totalup += Math.pow(Score[k] - m, 2.0) Totalup Math.pow(Score[k] - m, 2.0) Math.pow Math Score[k] - m Score[k] Score k m 2.0 a = Totalup / n a Totalup / n Totalup n b = Math.pow(a, 0.5) b Math.pow(a, 0.5) Math.pow Math a 0.5 System.out.println(b) System.out.println System.out System System.out b String[] args args public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int i, j, k;
        double a, b, m, n;
        double[] Score = new double[10000];
        for(i = 0; ; i++){
            int Total = 0;
            double Totalup = 0.0;
            n = sc.nextDouble();
            if(n == 0.0){
                break;
            } else{
                for(j = 0; j < n; j++){
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                }
                m = Total / n;
            }
            for(k = 0; k < n; k++){
                Totalup += Math.pow(Score[k] - m, 2.0);
            }
            a = Totalup / n;
            b = Math.pow(a, 0.5);
            System.out.println(b);
        }
    }
} public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int i, j, k;
        double a, b, m, n;
        double[] Score = new double[10000];
        for(i = 0; ; i++){
            int Total = 0;
            double Totalup = 0.0;
            n = sc.nextDouble();
            if(n == 0.0){
                break;
            } else{
                for(j = 0; j < n; j++){
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                }
                m = Total / n;
            }
            for(k = 0; k < n; k++){
                Totalup += Math.pow(Score[k] - m, 2.0);
            }
            a = Totalup / n;
            b = Math.pow(a, 0.5);
            System.out.println(b);
        }
    }
} Main
import java.util.Scanner;

public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int i, j, k;
        double a, b, m, n;
        double[] Score = new double[10000];
        for(i = 0; ; i++){
            int Total = 0;
            double Totalup = 0.0;
            n = sc.nextDouble();
            if(n == 0.0){
                break;
            } else{
                for(j = 0; j < n; j++){
                    Score[j] = sc.nextDouble();
                    Total += Score[j];
                }
                m = Total / n;
            }
            for(k = 0; k < n; k++){
                Totalup += Math.pow(Score[k] - m, 2.0);
            }
            a = Totalup / n;
            b = Math.pow(a, 0.5);
            System.out.println(b);
        }
    }
}
