import java.util.Scanner;

public class Main{
	public static void main(String[] args){		
		//データの入力の準備
		Scanner sc = new Scanner(System.in);
		
		while (true){
			int num;
			double sum = 0;
			double ave;
			double bunsan = 0;
			
			num = sc.nextInt();
			
			//終了条件の判定
			if (num == 0){
				break;
			}
		
			//データ格納用配列
			double[] datas = new double[num];
		
			//データの入力
			for (int i = 0; i < num;i++){
				double temp = sc.nextDouble();
				sum += temp;
				datas[i] = temp;
			}
		
			//平均を求める
			ave = sum / num;
		
			//分散を計算
			for (int i = 0; i < num; i++){
				bunsan += Math.pow((datas[i] - ave), 2);
			}
			bunsan /= num;
		
			System.out.printf("%f\n",Math.sqrt(bunsan));
		}
	}
} import java.util.Scanner; Scanner java.util public class Main{
	public static void main(String[] args){		
		//データの入力の準備
		Scanner sc = new Scanner(System.in);
		
		while (true){
			int num;
			double sum = 0;
			double ave;
			double bunsan = 0;
			
			num = sc.nextInt();
			
			//終了条件の判定
			if (num == 0){
				break;
			}
		
			//データ格納用配列
			double[] datas = new double[num];
		
			//データの入力
			for (int i = 0; i < num;i++){
				double temp = sc.nextDouble();
				sum += temp;
				datas[i] = temp;
			}
		
			//平均を求める
			ave = sum / num;
		
			//分散を計算
			for (int i = 0; i < num; i++){
				bunsan += Math.pow((datas[i] - ave), 2);
			}
			bunsan /= num;
		
			System.out.printf("%f\n",Math.sqrt(bunsan));
		}
	}
} Main public static void main(String[] args){		
		//データの入力の準備
		Scanner sc = new Scanner(System.in);
		
		while (true){
			int num;
			double sum = 0;
			double ave;
			double bunsan = 0;
			
			num = sc.nextInt();
			
			//終了条件の判定
			if (num == 0){
				break;
			}
		
			//データ格納用配列
			double[] datas = new double[num];
		
			//データの入力
			for (int i = 0; i < num;i++){
				double temp = sc.nextDouble();
				sum += temp;
				datas[i] = temp;
			}
		
			//平均を求める
			ave = sum / num;
		
			//分散を計算
			for (int i = 0; i < num; i++){
				bunsan += Math.pow((datas[i] - ave), 2);
			}
			bunsan /= num;
		
			System.out.printf("%f\n",Math.sqrt(bunsan));
		}
	} main {		
		//データの入力の準備
		Scanner sc = new Scanner(System.in);
		
		while (true){
			int num;
			double sum = 0;
			double ave;
			double bunsan = 0;
			
			num = sc.nextInt();
			
			//終了条件の判定
			if (num == 0){
				break;
			}
		
			//データ格納用配列
			double[] datas = new double[num];
		
			//データの入力
			for (int i = 0; i < num;i++){
				double temp = sc.nextDouble();
				sum += temp;
				datas[i] = temp;
			}
		
			//平均を求める
			ave = sum / num;
		
			//分散を計算
			for (int i = 0; i < num; i++){
				bunsan += Math.pow((datas[i] - ave), 2);
			}
			bunsan /= num;
		
			System.out.printf("%f\n",Math.sqrt(bunsan));
		}
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) while (true){
			int num;
			double sum = 0;
			double ave;
			double bunsan = 0;
			
			num = sc.nextInt();
			
			//終了条件の判定
			if (num == 0){
				break;
			}
		
			//データ格納用配列
			double[] datas = new double[num];
		
			//データの入力
			for (int i = 0; i < num;i++){
				double temp = sc.nextDouble();
				sum += temp;
				datas[i] = temp;
			}
		
			//平均を求める
			ave = sum / num;
		
			//分散を計算
			for (int i = 0; i < num; i++){
				bunsan += Math.pow((datas[i] - ave), 2);
			}
			bunsan /= num;
		
			System.out.printf("%f\n",Math.sqrt(bunsan));
		} true {
			int num;
			double sum = 0;
			double ave;
			double bunsan = 0;
			
			num = sc.nextInt();
			
			//終了条件の判定
			if (num == 0){
				break;
			}
		
			//データ格納用配列
			double[] datas = new double[num];
		
			//データの入力
			for (int i = 0; i < num;i++){
				double temp = sc.nextDouble();
				sum += temp;
				datas[i] = temp;
			}
		
			//平均を求める
			ave = sum / num;
		
			//分散を計算
			for (int i = 0; i < num; i++){
				bunsan += Math.pow((datas[i] - ave), 2);
			}
			bunsan /= num;
		
			System.out.printf("%f\n",Math.sqrt(bunsan));
		} int num; num double sum = 0; sum 0 double ave; ave double bunsan = 0; bunsan 0 num = sc.nextInt() num sc.nextInt() sc.nextInt sc if (num == 0){
				break;
			} num == 0 num 0 {
				break;
			} break; double[] datas = new double[num]; datas new double[num] num for (int i = 0; i < num;i++){
				double temp = sc.nextDouble();
				sum += temp;
				datas[i] = temp;
			} int i = 0; int i = 0; i 0 i < num i num i++ i++ i {
				double temp = sc.nextDouble();
				sum += temp;
				datas[i] = temp;
			} {
				double temp = sc.nextDouble();
				sum += temp;
				datas[i] = temp;
			} double temp = sc.nextDouble(); temp sc.nextDouble() sc.nextDouble sc sum += temp sum temp datas[i] = temp datas[i] datas i temp ave = sum / num ave sum / num sum num for (int i = 0; i < num; i++){
				bunsan += Math.pow((datas[i] - ave), 2);
			} int i = 0; int i = 0; i 0 i < num i num i++ i++ i {
				bunsan += Math.pow((datas[i] - ave), 2);
			} {
				bunsan += Math.pow((datas[i] - ave), 2);
			} bunsan += Math.pow((datas[i] - ave), 2) bunsan Math.pow((datas[i] - ave), 2) Math.pow Math (datas[i] - ave) datas[i] datas i ave 2 bunsan /= num bunsan num System.out.printf("%f\n",Math.sqrt(bunsan)) System.out.printf System.out System System.out "%f\n" Math.sqrt(bunsan) Math.sqrt Math bunsan String[] args args public class Main{
	public static void main(String[] args){		
		//データの入力の準備
		Scanner sc = new Scanner(System.in);
		
		while (true){
			int num;
			double sum = 0;
			double ave;
			double bunsan = 0;
			
			num = sc.nextInt();
			
			//終了条件の判定
			if (num == 0){
				break;
			}
		
			//データ格納用配列
			double[] datas = new double[num];
		
			//データの入力
			for (int i = 0; i < num;i++){
				double temp = sc.nextDouble();
				sum += temp;
				datas[i] = temp;
			}
		
			//平均を求める
			ave = sum / num;
		
			//分散を計算
			for (int i = 0; i < num; i++){
				bunsan += Math.pow((datas[i] - ave), 2);
			}
			bunsan /= num;
		
			System.out.printf("%f\n",Math.sqrt(bunsan));
		}
	}
} public class Main{
	public static void main(String[] args){		
		//データの入力の準備
		Scanner sc = new Scanner(System.in);
		
		while (true){
			int num;
			double sum = 0;
			double ave;
			double bunsan = 0;
			
			num = sc.nextInt();
			
			//終了条件の判定
			if (num == 0){
				break;
			}
		
			//データ格納用配列
			double[] datas = new double[num];
		
			//データの入力
			for (int i = 0; i < num;i++){
				double temp = sc.nextDouble();
				sum += temp;
				datas[i] = temp;
			}
		
			//平均を求める
			ave = sum / num;
		
			//分散を計算
			for (int i = 0; i < num; i++){
				bunsan += Math.pow((datas[i] - ave), 2);
			}
			bunsan /= num;
		
			System.out.printf("%f\n",Math.sqrt(bunsan));
		}
	}
} Main
import java.util.Scanner;

public class Main{
	public static void main(String[] args){		
		//データの入力の準備
		Scanner sc = new Scanner(System.in);
		
		while (true){
			int num;
			double sum = 0;
			double ave;
			double bunsan = 0;
			
			num = sc.nextInt();
			
			//終了条件の判定
			if (num == 0){
				break;
			}
		
			//データ格納用配列
			double[] datas = new double[num];
		
			//データの入力
			for (int i = 0; i < num;i++){
				double temp = sc.nextDouble();
				sum += temp;
				datas[i] = temp;
			}
		
			//平均を求める
			ave = sum / num;
		
			//分散を計算
			for (int i = 0; i < num; i++){
				bunsan += Math.pow((datas[i] - ave), 2);
			}
			bunsan /= num;
		
			System.out.printf("%f\n",Math.sqrt(bunsan));
		}
	}
}
