import java.util.Scanner;

public class Main{

	public static void main(String[] args) {
        Scanner sc =new Scanner(System.in);

        while(true){
    		double total = 0.0; //合計点
            double m = 0.0; //平均点
            double a = 0.0; //分散
            double stdev = 0.0;

            //学生の数
            int n = Integer.parseInt(sc.next());
        	if(n==0){
        		break;
        	}
        	//入力した分だけの配列内変数作成
        	int points[] = new int[n];

        	//合計
            for (int i=0; i<n; i++) {
                points[i] = Integer.parseInt(sc.next());
                total += points[i];
            }

            //平均
            m = total / n;

            //分散
            for (int i=0; i<n; i++) {
                a += ((points[i] - m)*(points[i] - m));
            }

            //標準偏差
            stdev = Math.sqrt(a/n);
            System.out.println(stdev);
        }
	}

}
 import java.util.Scanner; Scanner java.util public class Main{

	public static void main(String[] args) {
        Scanner sc =new Scanner(System.in);

        while(true){
    		double total = 0.0; //合計点
            double m = 0.0; //平均点
            double a = 0.0; //分散
            double stdev = 0.0;

            //学生の数
            int n = Integer.parseInt(sc.next());
        	if(n==0){
        		break;
        	}
        	//入力した分だけの配列内変数作成
        	int points[] = new int[n];

        	//合計
            for (int i=0; i<n; i++) {
                points[i] = Integer.parseInt(sc.next());
                total += points[i];
            }

            //平均
            m = total / n;

            //分散
            for (int i=0; i<n; i++) {
                a += ((points[i] - m)*(points[i] - m));
            }

            //標準偏差
            stdev = Math.sqrt(a/n);
            System.out.println(stdev);
        }
	}

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

        while(true){
    		double total = 0.0; //合計点
            double m = 0.0; //平均点
            double a = 0.0; //分散
            double stdev = 0.0;

            //学生の数
            int n = Integer.parseInt(sc.next());
        	if(n==0){
        		break;
        	}
        	//入力した分だけの配列内変数作成
        	int points[] = new int[n];

        	//合計
            for (int i=0; i<n; i++) {
                points[i] = Integer.parseInt(sc.next());
                total += points[i];
            }

            //平均
            m = total / n;

            //分散
            for (int i=0; i<n; i++) {
                a += ((points[i] - m)*(points[i] - m));
            }

            //標準偏差
            stdev = Math.sqrt(a/n);
            System.out.println(stdev);
        }
	} main {
        Scanner sc =new Scanner(System.in);

        while(true){
    		double total = 0.0; //合計点
            double m = 0.0; //平均点
            double a = 0.0; //分散
            double stdev = 0.0;

            //学生の数
            int n = Integer.parseInt(sc.next());
        	if(n==0){
        		break;
        	}
        	//入力した分だけの配列内変数作成
        	int points[] = new int[n];

        	//合計
            for (int i=0; i<n; i++) {
                points[i] = Integer.parseInt(sc.next());
                total += points[i];
            }

            //平均
            m = total / n;

            //分散
            for (int i=0; i<n; i++) {
                a += ((points[i] - m)*(points[i] - m));
            }

            //標準偏差
            stdev = Math.sqrt(a/n);
            System.out.println(stdev);
        }
	} Scanner sc =new Scanner(System.in); sc new Scanner(System.in) while(true){
    		double total = 0.0; //合計点
            double m = 0.0; //平均点
            double a = 0.0; //分散
            double stdev = 0.0;

            //学生の数
            int n = Integer.parseInt(sc.next());
        	if(n==0){
        		break;
        	}
        	//入力した分だけの配列内変数作成
        	int points[] = new int[n];

        	//合計
            for (int i=0; i<n; i++) {
                points[i] = Integer.parseInt(sc.next());
                total += points[i];
            }

            //平均
            m = total / n;

            //分散
            for (int i=0; i<n; i++) {
                a += ((points[i] - m)*(points[i] - m));
            }

            //標準偏差
            stdev = Math.sqrt(a/n);
            System.out.println(stdev);
        } true {
    		double total = 0.0; //合計点
            double m = 0.0; //平均点
            double a = 0.0; //分散
            double stdev = 0.0;

            //学生の数
            int n = Integer.parseInt(sc.next());
        	if(n==0){
        		break;
        	}
        	//入力した分だけの配列内変数作成
        	int points[] = new int[n];

        	//合計
            for (int i=0; i<n; i++) {
                points[i] = Integer.parseInt(sc.next());
                total += points[i];
            }

            //平均
            m = total / n;

            //分散
            for (int i=0; i<n; i++) {
                a += ((points[i] - m)*(points[i] - m));
            }

            //標準偏差
            stdev = Math.sqrt(a/n);
            System.out.println(stdev);
        } double total = 0.0; total 0.0 double m = 0.0; m 0.0 double a = 0.0; a 0.0 double stdev = 0.0; stdev 0.0 int n = Integer.parseInt(sc.next()); n Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc if(n==0){
        		break;
        	} n==0 n 0 {
        		break;
        	} break; int points[] = new int[n]; points new int[n] n for (int i=0; i<n; i++) {
                points[i] = Integer.parseInt(sc.next());
                total += points[i];
            } int i=0; int i=0; i 0 i<n i n i++ i++ i {
                points[i] = Integer.parseInt(sc.next());
                total += points[i];
            } {
                points[i] = Integer.parseInt(sc.next());
                total += points[i];
            } points[i] = Integer.parseInt(sc.next()) points[i] points i Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc total += points[i] total points[i] points i m = total / n m total / n total n for (int i=0; i<n; i++) {
                a += ((points[i] - m)*(points[i] - m));
            } int i=0; int i=0; i 0 i<n i n i++ i++ i {
                a += ((points[i] - m)*(points[i] - m));
            } {
                a += ((points[i] - m)*(points[i] - m));
            } a += ((points[i] - m)*(points[i] - m)) a ((points[i] - m)*(points[i] - m)) (points[i] - m) points[i] points i m (points[i] - m) points[i] points i m stdev = Math.sqrt(a/n) stdev Math.sqrt(a/n) Math.sqrt Math a/n a n System.out.println(stdev) System.out.println System.out System System.out stdev String[] args args public class Main{

	public static void main(String[] args) {
        Scanner sc =new Scanner(System.in);

        while(true){
    		double total = 0.0; //合計点
            double m = 0.0; //平均点
            double a = 0.0; //分散
            double stdev = 0.0;

            //学生の数
            int n = Integer.parseInt(sc.next());
        	if(n==0){
        		break;
        	}
        	//入力した分だけの配列内変数作成
        	int points[] = new int[n];

        	//合計
            for (int i=0; i<n; i++) {
                points[i] = Integer.parseInt(sc.next());
                total += points[i];
            }

            //平均
            m = total / n;

            //分散
            for (int i=0; i<n; i++) {
                a += ((points[i] - m)*(points[i] - m));
            }

            //標準偏差
            stdev = Math.sqrt(a/n);
            System.out.println(stdev);
        }
	}

} public class Main{

	public static void main(String[] args) {
        Scanner sc =new Scanner(System.in);

        while(true){
    		double total = 0.0; //合計点
            double m = 0.0; //平均点
            double a = 0.0; //分散
            double stdev = 0.0;

            //学生の数
            int n = Integer.parseInt(sc.next());
        	if(n==0){
        		break;
        	}
        	//入力した分だけの配列内変数作成
        	int points[] = new int[n];

        	//合計
            for (int i=0; i<n; i++) {
                points[i] = Integer.parseInt(sc.next());
                total += points[i];
            }

            //平均
            m = total / n;

            //分散
            for (int i=0; i<n; i++) {
                a += ((points[i] - m)*(points[i] - m));
            }

            //標準偏差
            stdev = Math.sqrt(a/n);
            System.out.println(stdev);
        }
	}

} Main
import java.util.Scanner;

public class Main{

	public static void main(String[] args) {
        Scanner sc =new Scanner(System.in);

        while(true){
    		double total = 0.0; //合計点
            double m = 0.0; //平均点
            double a = 0.0; //分散
            double stdev = 0.0;

            //学生の数
            int n = Integer.parseInt(sc.next());
        	if(n==0){
        		break;
        	}
        	//入力した分だけの配列内変数作成
        	int points[] = new int[n];

        	//合計
            for (int i=0; i<n; i++) {
                points[i] = Integer.parseInt(sc.next());
                total += points[i];
            }

            //平均
            m = total / n;

            //分散
            for (int i=0; i<n; i++) {
                a += ((points[i] - m)*(points[i] - m));
            }

            //標準偏差
            stdev = Math.sqrt(a/n);
            System.out.println(stdev);
        }
	}

}

