import java.util.Scanner;

public class Main{

	public static void main(String[] args) {
		// TODO ?????????????????????????????????????????????

		Scanner scan = new Scanner(System.in);

		while(true){

			//?????°?????????
			int n = scan.nextInt();
			//????????¢???????´?????????????
			double[] score = new double[n];
			//????¨????????????????????????°
			double total = 0.0;
			//?????????????????????????????°
			double average = 0.0;
			//?????£????????????????????°
			double var = 0.0;
			//?¨?????????????????????????????????°
			double result = 0.0;

			//???????????¶
			if(n==0){
				scan.close();
				break;
			}else{

				for(int i = 0; i < n; i++){
					score[i] = scan.nextDouble();
					total += score[i];
				}
				//?????????
				average = total / n;
				//?????£????¨????
				double temp = 0.0;
				for(int j = 0; j < n; j++){
					temp += Math.pow(score[j] - average ,2);
				}
				var = temp/n;
			}

			//?¨?????????????????±?????????¬???
			//?????£????????????????±???????
			result = Math.sqrt(var);
			System.out.println(result);
		}
	}

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

	public static void main(String[] args) {
		// TODO ?????????????????????????????????????????????

		Scanner scan = new Scanner(System.in);

		while(true){

			//?????°?????????
			int n = scan.nextInt();
			//????????¢???????´?????????????
			double[] score = new double[n];
			//????¨????????????????????????°
			double total = 0.0;
			//?????????????????????????????°
			double average = 0.0;
			//?????£????????????????????°
			double var = 0.0;
			//?¨?????????????????????????????????°
			double result = 0.0;

			//???????????¶
			if(n==0){
				scan.close();
				break;
			}else{

				for(int i = 0; i < n; i++){
					score[i] = scan.nextDouble();
					total += score[i];
				}
				//?????????
				average = total / n;
				//?????£????¨????
				double temp = 0.0;
				for(int j = 0; j < n; j++){
					temp += Math.pow(score[j] - average ,2);
				}
				var = temp/n;
			}

			//?¨?????????????????±?????????¬???
			//?????£????????????????±???????
			result = Math.sqrt(var);
			System.out.println(result);
		}
	}

} Main public static void main(String[] args) {
		// TODO ?????????????????????????????????????????????

		Scanner scan = new Scanner(System.in);

		while(true){

			//?????°?????????
			int n = scan.nextInt();
			//????????¢???????´?????????????
			double[] score = new double[n];
			//????¨????????????????????????°
			double total = 0.0;
			//?????????????????????????????°
			double average = 0.0;
			//?????£????????????????????°
			double var = 0.0;
			//?¨?????????????????????????????????°
			double result = 0.0;

			//???????????¶
			if(n==0){
				scan.close();
				break;
			}else{

				for(int i = 0; i < n; i++){
					score[i] = scan.nextDouble();
					total += score[i];
				}
				//?????????
				average = total / n;
				//?????£????¨????
				double temp = 0.0;
				for(int j = 0; j < n; j++){
					temp += Math.pow(score[j] - average ,2);
				}
				var = temp/n;
			}

			//?¨?????????????????±?????????¬???
			//?????£????????????????±???????
			result = Math.sqrt(var);
			System.out.println(result);
		}
	} main {
		// TODO ?????????????????????????????????????????????

		Scanner scan = new Scanner(System.in);

		while(true){

			//?????°?????????
			int n = scan.nextInt();
			//????????¢???????´?????????????
			double[] score = new double[n];
			//????¨????????????????????????°
			double total = 0.0;
			//?????????????????????????????°
			double average = 0.0;
			//?????£????????????????????°
			double var = 0.0;
			//?¨?????????????????????????????????°
			double result = 0.0;

			//???????????¶
			if(n==0){
				scan.close();
				break;
			}else{

				for(int i = 0; i < n; i++){
					score[i] = scan.nextDouble();
					total += score[i];
				}
				//?????????
				average = total / n;
				//?????£????¨????
				double temp = 0.0;
				for(int j = 0; j < n; j++){
					temp += Math.pow(score[j] - average ,2);
				}
				var = temp/n;
			}

			//?¨?????????????????±?????????¬???
			//?????£????????????????±???????
			result = Math.sqrt(var);
			System.out.println(result);
		}
	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) while(true){

			//?????°?????????
			int n = scan.nextInt();
			//????????¢???????´?????????????
			double[] score = new double[n];
			//????¨????????????????????????°
			double total = 0.0;
			//?????????????????????????????°
			double average = 0.0;
			//?????£????????????????????°
			double var = 0.0;
			//?¨?????????????????????????????????°
			double result = 0.0;

			//???????????¶
			if(n==0){
				scan.close();
				break;
			}else{

				for(int i = 0; i < n; i++){
					score[i] = scan.nextDouble();
					total += score[i];
				}
				//?????????
				average = total / n;
				//?????£????¨????
				double temp = 0.0;
				for(int j = 0; j < n; j++){
					temp += Math.pow(score[j] - average ,2);
				}
				var = temp/n;
			}

			//?¨?????????????????±?????????¬???
			//?????£????????????????±???????
			result = Math.sqrt(var);
			System.out.println(result);
		} true {

			//?????°?????????
			int n = scan.nextInt();
			//????????¢???????´?????????????
			double[] score = new double[n];
			//????¨????????????????????????°
			double total = 0.0;
			//?????????????????????????????°
			double average = 0.0;
			//?????£????????????????????°
			double var = 0.0;
			//?¨?????????????????????????????????°
			double result = 0.0;

			//???????????¶
			if(n==0){
				scan.close();
				break;
			}else{

				for(int i = 0; i < n; i++){
					score[i] = scan.nextDouble();
					total += score[i];
				}
				//?????????
				average = total / n;
				//?????£????¨????
				double temp = 0.0;
				for(int j = 0; j < n; j++){
					temp += Math.pow(score[j] - average ,2);
				}
				var = temp/n;
			}

			//?¨?????????????????±?????????¬???
			//?????£????????????????±???????
			result = Math.sqrt(var);
			System.out.println(result);
		} int n = scan.nextInt(); n scan.nextInt() scan.nextInt scan double[] score = new double[n]; score new double[n] n double total = 0.0; total 0.0 double average = 0.0; average 0.0 double var = 0.0; var 0.0 double result = 0.0; result 0.0 if(n==0){
				scan.close();
				break;
			}else{

				for(int i = 0; i < n; i++){
					score[i] = scan.nextDouble();
					total += score[i];
				}
				//?????????
				average = total / n;
				//?????£????¨????
				double temp = 0.0;
				for(int j = 0; j < n; j++){
					temp += Math.pow(score[j] - average ,2);
				}
				var = temp/n;
			} n==0 n 0 {
				scan.close();
				break;
			} scan.close() scan.close scan break; {

				for(int i = 0; i < n; i++){
					score[i] = scan.nextDouble();
					total += score[i];
				}
				//?????????
				average = total / n;
				//?????£????¨????
				double temp = 0.0;
				for(int j = 0; j < n; j++){
					temp += Math.pow(score[j] - average ,2);
				}
				var = temp/n;
			} for(int i = 0; i < n; i++){
					score[i] = scan.nextDouble();
					total += score[i];
				} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
					score[i] = scan.nextDouble();
					total += score[i];
				} {
					score[i] = scan.nextDouble();
					total += score[i];
				} score[i] = scan.nextDouble() score[i] score i scan.nextDouble() scan.nextDouble scan total += score[i] total score[i] score i average = total / n average total / n total n double temp = 0.0; temp 0.0 for(int j = 0; j < n; j++){
					temp += Math.pow(score[j] - average ,2);
				} int j = 0; int j = 0; j 0 j < n j n j++ j++ j {
					temp += Math.pow(score[j] - average ,2);
				} {
					temp += Math.pow(score[j] - average ,2);
				} temp += Math.pow(score[j] - average ,2) temp Math.pow(score[j] - average ,2) Math.pow Math score[j] - average score[j] score j average 2 var = temp/n var temp/n temp n result = Math.sqrt(var) result Math.sqrt(var) Math.sqrt Math var System.out.println(result) System.out.println System.out System System.out result String[] args args public class Main{

	public static void main(String[] args) {
		// TODO ?????????????????????????????????????????????

		Scanner scan = new Scanner(System.in);

		while(true){

			//?????°?????????
			int n = scan.nextInt();
			//????????¢???????´?????????????
			double[] score = new double[n];
			//????¨????????????????????????°
			double total = 0.0;
			//?????????????????????????????°
			double average = 0.0;
			//?????£????????????????????°
			double var = 0.0;
			//?¨?????????????????????????????????°
			double result = 0.0;

			//???????????¶
			if(n==0){
				scan.close();
				break;
			}else{

				for(int i = 0; i < n; i++){
					score[i] = scan.nextDouble();
					total += score[i];
				}
				//?????????
				average = total / n;
				//?????£????¨????
				double temp = 0.0;
				for(int j = 0; j < n; j++){
					temp += Math.pow(score[j] - average ,2);
				}
				var = temp/n;
			}

			//?¨?????????????????±?????????¬???
			//?????£????????????????±???????
			result = Math.sqrt(var);
			System.out.println(result);
		}
	}

} public class Main{

	public static void main(String[] args) {
		// TODO ?????????????????????????????????????????????

		Scanner scan = new Scanner(System.in);

		while(true){

			//?????°?????????
			int n = scan.nextInt();
			//????????¢???????´?????????????
			double[] score = new double[n];
			//????¨????????????????????????°
			double total = 0.0;
			//?????????????????????????????°
			double average = 0.0;
			//?????£????????????????????°
			double var = 0.0;
			//?¨?????????????????????????????????°
			double result = 0.0;

			//???????????¶
			if(n==0){
				scan.close();
				break;
			}else{

				for(int i = 0; i < n; i++){
					score[i] = scan.nextDouble();
					total += score[i];
				}
				//?????????
				average = total / n;
				//?????£????¨????
				double temp = 0.0;
				for(int j = 0; j < n; j++){
					temp += Math.pow(score[j] - average ,2);
				}
				var = temp/n;
			}

			//?¨?????????????????±?????????¬???
			//?????£????????????????±???????
			result = Math.sqrt(var);
			System.out.println(result);
		}
	}

} Main
import java.util.Scanner;

public class Main{

	public static void main(String[] args) {
		// TODO ?????????????????????????????????????????????

		Scanner scan = new Scanner(System.in);

		while(true){

			//?????°?????????
			int n = scan.nextInt();
			//????????¢???????´?????????????
			double[] score = new double[n];
			//????¨????????????????????????°
			double total = 0.0;
			//?????????????????????????????°
			double average = 0.0;
			//?????£????????????????????°
			double var = 0.0;
			//?¨?????????????????????????????????°
			double result = 0.0;

			//???????????¶
			if(n==0){
				scan.close();
				break;
			}else{

				for(int i = 0; i < n; i++){
					score[i] = scan.nextDouble();
					total += score[i];
				}
				//?????????
				average = total / n;
				//?????£????¨????
				double temp = 0.0;
				for(int j = 0; j < n; j++){
					temp += Math.pow(score[j] - average ,2);
				}
				var = temp/n;
			}

			//?¨?????????????????±?????????¬???
			//?????£????????????????±???????
			result = Math.sqrt(var);
			System.out.println(result);
		}
	}

}