import java.util.Scanner;
public class Main {
    public static void main(String[] args){
        Scanner scan=new Scanner(System.in);
        int n;

        while(true){
            n=scan.nextInt();
            if(n==0) break;
            int[] score=new int[n];
            double ave=0;
            for(int i=0;i<n;i++){
                score[i]=scan.nextInt();
                ave+=score[i];
            }
            ave/=(double)n;
            double dis=0;
            for(int i=0;i<n;i++) dis+=(score[i]-ave)*(score[i]-ave);
            dis/=(double)n;
            System.out.println(Math.sqrt(dis));
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args){
        Scanner scan=new Scanner(System.in);
        int n;

        while(true){
            n=scan.nextInt();
            if(n==0) break;
            int[] score=new int[n];
            double ave=0;
            for(int i=0;i<n;i++){
                score[i]=scan.nextInt();
                ave+=score[i];
            }
            ave/=(double)n;
            double dis=0;
            for(int i=0;i<n;i++) dis+=(score[i]-ave)*(score[i]-ave);
            dis/=(double)n;
            System.out.println(Math.sqrt(dis));
        }
    }
} Main public static void main(String[] args){
        Scanner scan=new Scanner(System.in);
        int n;

        while(true){
            n=scan.nextInt();
            if(n==0) break;
            int[] score=new int[n];
            double ave=0;
            for(int i=0;i<n;i++){
                score[i]=scan.nextInt();
                ave+=score[i];
            }
            ave/=(double)n;
            double dis=0;
            for(int i=0;i<n;i++) dis+=(score[i]-ave)*(score[i]-ave);
            dis/=(double)n;
            System.out.println(Math.sqrt(dis));
        }
    } main {
        Scanner scan=new Scanner(System.in);
        int n;

        while(true){
            n=scan.nextInt();
            if(n==0) break;
            int[] score=new int[n];
            double ave=0;
            for(int i=0;i<n;i++){
                score[i]=scan.nextInt();
                ave+=score[i];
            }
            ave/=(double)n;
            double dis=0;
            for(int i=0;i<n;i++) dis+=(score[i]-ave)*(score[i]-ave);
            dis/=(double)n;
            System.out.println(Math.sqrt(dis));
        }
    } Scanner scan=new Scanner(System.in); scan new Scanner(System.in) int n; n while(true){
            n=scan.nextInt();
            if(n==0) break;
            int[] score=new int[n];
            double ave=0;
            for(int i=0;i<n;i++){
                score[i]=scan.nextInt();
                ave+=score[i];
            }
            ave/=(double)n;
            double dis=0;
            for(int i=0;i<n;i++) dis+=(score[i]-ave)*(score[i]-ave);
            dis/=(double)n;
            System.out.println(Math.sqrt(dis));
        } true {
            n=scan.nextInt();
            if(n==0) break;
            int[] score=new int[n];
            double ave=0;
            for(int i=0;i<n;i++){
                score[i]=scan.nextInt();
                ave+=score[i];
            }
            ave/=(double)n;
            double dis=0;
            for(int i=0;i<n;i++) dis+=(score[i]-ave)*(score[i]-ave);
            dis/=(double)n;
            System.out.println(Math.sqrt(dis));
        } n=scan.nextInt() n scan.nextInt() scan.nextInt scan if(n==0) break; n==0 n 0 break; int[] score=new int[n]; score new int[n] n double ave=0; ave 0 for(int i=0;i<n;i++){
                score[i]=scan.nextInt();
                ave+=score[i];
            } int i=0; int i=0; i 0 i<n i n i++ i++ i {
                score[i]=scan.nextInt();
                ave+=score[i];
            } {
                score[i]=scan.nextInt();
                ave+=score[i];
            } score[i]=scan.nextInt() score[i] score i scan.nextInt() scan.nextInt scan ave+=score[i] ave score[i] score i ave/=(double)n ave (double)n double dis=0; dis 0 for(int i=0;i<n;i++) dis+=(score[i]-ave)*(score[i]-ave); int i=0; int i=0; i 0 i<n i n i++ i++ i dis+=(score[i]-ave)*(score[i]-ave); dis+=(score[i]-ave)*(score[i]-ave) dis (score[i]-ave)*(score[i]-ave) (score[i]-ave) score[i] score i ave (score[i]-ave) score[i] score i ave dis/=(double)n dis (double)n System.out.println(Math.sqrt(dis)) System.out.println System.out System System.out Math.sqrt(dis) Math.sqrt Math dis String[] args args public class Main {
    public static void main(String[] args){
        Scanner scan=new Scanner(System.in);
        int n;

        while(true){
            n=scan.nextInt();
            if(n==0) break;
            int[] score=new int[n];
            double ave=0;
            for(int i=0;i<n;i++){
                score[i]=scan.nextInt();
                ave+=score[i];
            }
            ave/=(double)n;
            double dis=0;
            for(int i=0;i<n;i++) dis+=(score[i]-ave)*(score[i]-ave);
            dis/=(double)n;
            System.out.println(Math.sqrt(dis));
        }
    }
} public class Main {
    public static void main(String[] args){
        Scanner scan=new Scanner(System.in);
        int n;

        while(true){
            n=scan.nextInt();
            if(n==0) break;
            int[] score=new int[n];
            double ave=0;
            for(int i=0;i<n;i++){
                score[i]=scan.nextInt();
                ave+=score[i];
            }
            ave/=(double)n;
            double dis=0;
            for(int i=0;i<n;i++) dis+=(score[i]-ave)*(score[i]-ave);
            dis/=(double)n;
            System.out.println(Math.sqrt(dis));
        }
    }
} Main
import java.util.Scanner;
public class Main {
    public static void main(String[] args){
        Scanner scan=new Scanner(System.in);
        int n;

        while(true){
            n=scan.nextInt();
            if(n==0) break;
            int[] score=new int[n];
            double ave=0;
            for(int i=0;i<n;i++){
                score[i]=scan.nextInt();
                ave+=score[i];
            }
            ave/=(double)n;
            double dis=0;
            for(int i=0;i<n;i++) dis+=(score[i]-ave)*(score[i]-ave);
            dis/=(double)n;
            System.out.println(Math.sqrt(dis));
        }
    }
}
