import java.util.Scanner;

public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int n = 100;

        while(true){
        n = sc.nextInt();
        if(n==0) break;
        double s[] = new double[n];
        double m, sum = 0d, sum2 = 0d;
        double result;

        for(int i=0; i<n; i++){
            s[i] = (double)sc.nextInt();
            sum += s[i]; 
        }
        m = sum / n;

        for(int i=0; i<n; i++){
            sum2 += Math.pow(s[i]-m, 2);
        }
        result = Math.sqrt(sum2/n); 

        System.out.printf("%.8f\n", result);
    }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int n = 100;

        while(true){
        n = sc.nextInt();
        if(n==0) break;
        double s[] = new double[n];
        double m, sum = 0d, sum2 = 0d;
        double result;

        for(int i=0; i<n; i++){
            s[i] = (double)sc.nextInt();
            sum += s[i]; 
        }
        m = sum / n;

        for(int i=0; i<n; i++){
            sum2 += Math.pow(s[i]-m, 2);
        }
        result = Math.sqrt(sum2/n); 

        System.out.printf("%.8f\n", result);
    }
    }
} Main public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int n = 100;

        while(true){
        n = sc.nextInt();
        if(n==0) break;
        double s[] = new double[n];
        double m, sum = 0d, sum2 = 0d;
        double result;

        for(int i=0; i<n; i++){
            s[i] = (double)sc.nextInt();
            sum += s[i]; 
        }
        m = sum / n;

        for(int i=0; i<n; i++){
            sum2 += Math.pow(s[i]-m, 2);
        }
        result = Math.sqrt(sum2/n); 

        System.out.printf("%.8f\n", result);
    }
    } main {
        Scanner sc = new Scanner(System.in);
        int n = 100;

        while(true){
        n = sc.nextInt();
        if(n==0) break;
        double s[] = new double[n];
        double m, sum = 0d, sum2 = 0d;
        double result;

        for(int i=0; i<n; i++){
            s[i] = (double)sc.nextInt();
            sum += s[i]; 
        }
        m = sum / n;

        for(int i=0; i<n; i++){
            sum2 += Math.pow(s[i]-m, 2);
        }
        result = Math.sqrt(sum2/n); 

        System.out.printf("%.8f\n", result);
    }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = 100; n 100 while(true){
        n = sc.nextInt();
        if(n==0) break;
        double s[] = new double[n];
        double m, sum = 0d, sum2 = 0d;
        double result;

        for(int i=0; i<n; i++){
            s[i] = (double)sc.nextInt();
            sum += s[i]; 
        }
        m = sum / n;

        for(int i=0; i<n; i++){
            sum2 += Math.pow(s[i]-m, 2);
        }
        result = Math.sqrt(sum2/n); 

        System.out.printf("%.8f\n", result);
    } true {
        n = sc.nextInt();
        if(n==0) break;
        double s[] = new double[n];
        double m, sum = 0d, sum2 = 0d;
        double result;

        for(int i=0; i<n; i++){
            s[i] = (double)sc.nextInt();
            sum += s[i]; 
        }
        m = sum / n;

        for(int i=0; i<n; i++){
            sum2 += Math.pow(s[i]-m, 2);
        }
        result = Math.sqrt(sum2/n); 

        System.out.printf("%.8f\n", result);
    } n = sc.nextInt() n sc.nextInt() sc.nextInt sc if(n==0) break; n==0 n 0 break; double s[] = new double[n]; s new double[n] n double m m sum = 0d sum 0d sum2 = 0d; sum2 0d double result; result for(int i=0; i<n; i++){
            s[i] = (double)sc.nextInt();
            sum += s[i]; 
        } int i=0; int i=0; i 0 i<n i n i++ i++ i {
            s[i] = (double)sc.nextInt();
            sum += s[i]; 
        } {
            s[i] = (double)sc.nextInt();
            sum += s[i]; 
        } s[i] = (double)sc.nextInt() s[i] s i (double)sc.nextInt() sc.nextInt sc sum += s[i] sum s[i] s i m = sum / n m sum / n sum n for(int i=0; i<n; i++){
            sum2 += Math.pow(s[i]-m, 2);
        } int i=0; int i=0; i 0 i<n i n i++ i++ i {
            sum2 += Math.pow(s[i]-m, 2);
        } {
            sum2 += Math.pow(s[i]-m, 2);
        } sum2 += Math.pow(s[i]-m, 2) sum2 Math.pow(s[i]-m, 2) Math.pow Math s[i]-m s[i] s i m 2 result = Math.sqrt(sum2/n) result Math.sqrt(sum2/n) Math.sqrt Math sum2/n sum2 n System.out.printf("%.8f\n", result) System.out.printf System.out System System.out "%.8f\n" result String args[] args public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int n = 100;

        while(true){
        n = sc.nextInt();
        if(n==0) break;
        double s[] = new double[n];
        double m, sum = 0d, sum2 = 0d;
        double result;

        for(int i=0; i<n; i++){
            s[i] = (double)sc.nextInt();
            sum += s[i]; 
        }
        m = sum / n;

        for(int i=0; i<n; i++){
            sum2 += Math.pow(s[i]-m, 2);
        }
        result = Math.sqrt(sum2/n); 

        System.out.printf("%.8f\n", result);
    }
    }
} public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int n = 100;

        while(true){
        n = sc.nextInt();
        if(n==0) break;
        double s[] = new double[n];
        double m, sum = 0d, sum2 = 0d;
        double result;

        for(int i=0; i<n; i++){
            s[i] = (double)sc.nextInt();
            sum += s[i]; 
        }
        m = sum / n;

        for(int i=0; i<n; i++){
            sum2 += Math.pow(s[i]-m, 2);
        }
        result = Math.sqrt(sum2/n); 

        System.out.printf("%.8f\n", result);
    }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int n = 100;

        while(true){
        n = sc.nextInt();
        if(n==0) break;
        double s[] = new double[n];
        double m, sum = 0d, sum2 = 0d;
        double result;

        for(int i=0; i<n; i++){
            s[i] = (double)sc.nextInt();
            sum += s[i]; 
        }
        m = sum / n;

        for(int i=0; i<n; i++){
            sum2 += Math.pow(s[i]-m, 2);
        }
        result = Math.sqrt(sum2/n); 

        System.out.printf("%.8f\n", result);
    }
    }
}
