import java.util.Scanner;

class Main {
	public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);
		double area = 0.f;
		double sum;
		double sta;
		double dev;
		double dev_w;
		double dev_sum;
		double ave;
		double var;
		boolean Judge = true;
		
		while(Judge){
			int  stu_num = scanner.nextInt();	//学生数
			if( stu_num == 0 ){
				break;
			}
			double stu[] = new double[stu_num];
			sum = 0;
			dev_sum = 0;
			dev_w = 0;
			
			//点数入れる処理
			for( int i = 0; i < stu_num ; i ++ ){
				stu[i] = scanner.nextDouble();
				sum += stu[i];
			}
			ave = sum / stu_num;		//平均
			
			//偏差を求めて2乗
			for( int i = 0; i < stu_num ; i ++ ){
				dev = ave - stu[i];
				dev_w = dev * dev;
				dev_sum += dev_w;
			}
			
			if(dev_sum != 0) {
				var = dev_sum / stu_num;		//分散
			}else {
				var = 0;
			}
			
			sta = Math.sqrt(var);
		
			System.out.println(sta);
		
		}
		
		scanner.close();
	}
}

 import java.util.Scanner; Scanner java.util class Main {
	public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);
		double area = 0.f;
		double sum;
		double sta;
		double dev;
		double dev_w;
		double dev_sum;
		double ave;
		double var;
		boolean Judge = true;
		
		while(Judge){
			int  stu_num = scanner.nextInt();	//学生数
			if( stu_num == 0 ){
				break;
			}
			double stu[] = new double[stu_num];
			sum = 0;
			dev_sum = 0;
			dev_w = 0;
			
			//点数入れる処理
			for( int i = 0; i < stu_num ; i ++ ){
				stu[i] = scanner.nextDouble();
				sum += stu[i];
			}
			ave = sum / stu_num;		//平均
			
			//偏差を求めて2乗
			for( int i = 0; i < stu_num ; i ++ ){
				dev = ave - stu[i];
				dev_w = dev * dev;
				dev_sum += dev_w;
			}
			
			if(dev_sum != 0) {
				var = dev_sum / stu_num;		//分散
			}else {
				var = 0;
			}
			
			sta = Math.sqrt(var);
		
			System.out.println(sta);
		
		}
		
		scanner.close();
	}
} Main public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);
		double area = 0.f;
		double sum;
		double sta;
		double dev;
		double dev_w;
		double dev_sum;
		double ave;
		double var;
		boolean Judge = true;
		
		while(Judge){
			int  stu_num = scanner.nextInt();	//学生数
			if( stu_num == 0 ){
				break;
			}
			double stu[] = new double[stu_num];
			sum = 0;
			dev_sum = 0;
			dev_w = 0;
			
			//点数入れる処理
			for( int i = 0; i < stu_num ; i ++ ){
				stu[i] = scanner.nextDouble();
				sum += stu[i];
			}
			ave = sum / stu_num;		//平均
			
			//偏差を求めて2乗
			for( int i = 0; i < stu_num ; i ++ ){
				dev = ave - stu[i];
				dev_w = dev * dev;
				dev_sum += dev_w;
			}
			
			if(dev_sum != 0) {
				var = dev_sum / stu_num;		//分散
			}else {
				var = 0;
			}
			
			sta = Math.sqrt(var);
		
			System.out.println(sta);
		
		}
		
		scanner.close();
	} main {
		Scanner scanner = new Scanner(System.in);
		double area = 0.f;
		double sum;
		double sta;
		double dev;
		double dev_w;
		double dev_sum;
		double ave;
		double var;
		boolean Judge = true;
		
		while(Judge){
			int  stu_num = scanner.nextInt();	//学生数
			if( stu_num == 0 ){
				break;
			}
			double stu[] = new double[stu_num];
			sum = 0;
			dev_sum = 0;
			dev_w = 0;
			
			//点数入れる処理
			for( int i = 0; i < stu_num ; i ++ ){
				stu[i] = scanner.nextDouble();
				sum += stu[i];
			}
			ave = sum / stu_num;		//平均
			
			//偏差を求めて2乗
			for( int i = 0; i < stu_num ; i ++ ){
				dev = ave - stu[i];
				dev_w = dev * dev;
				dev_sum += dev_w;
			}
			
			if(dev_sum != 0) {
				var = dev_sum / stu_num;		//分散
			}else {
				var = 0;
			}
			
			sta = Math.sqrt(var);
		
			System.out.println(sta);
		
		}
		
		scanner.close();
	} Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) double area = 0.f; area 0.f double sum; sum double sta; sta double dev; dev double dev_w; dev_w double dev_sum; dev_sum double ave; ave double var; var boolean Judge = true; Judge true while(Judge){
			int  stu_num = scanner.nextInt();	//学生数
			if( stu_num == 0 ){
				break;
			}
			double stu[] = new double[stu_num];
			sum = 0;
			dev_sum = 0;
			dev_w = 0;
			
			//点数入れる処理
			for( int i = 0; i < stu_num ; i ++ ){
				stu[i] = scanner.nextDouble();
				sum += stu[i];
			}
			ave = sum / stu_num;		//平均
			
			//偏差を求めて2乗
			for( int i = 0; i < stu_num ; i ++ ){
				dev = ave - stu[i];
				dev_w = dev * dev;
				dev_sum += dev_w;
			}
			
			if(dev_sum != 0) {
				var = dev_sum / stu_num;		//分散
			}else {
				var = 0;
			}
			
			sta = Math.sqrt(var);
		
			System.out.println(sta);
		
		} Judge {
			int  stu_num = scanner.nextInt();	//学生数
			if( stu_num == 0 ){
				break;
			}
			double stu[] = new double[stu_num];
			sum = 0;
			dev_sum = 0;
			dev_w = 0;
			
			//点数入れる処理
			for( int i = 0; i < stu_num ; i ++ ){
				stu[i] = scanner.nextDouble();
				sum += stu[i];
			}
			ave = sum / stu_num;		//平均
			
			//偏差を求めて2乗
			for( int i = 0; i < stu_num ; i ++ ){
				dev = ave - stu[i];
				dev_w = dev * dev;
				dev_sum += dev_w;
			}
			
			if(dev_sum != 0) {
				var = dev_sum / stu_num;		//分散
			}else {
				var = 0;
			}
			
			sta = Math.sqrt(var);
		
			System.out.println(sta);
		
		} int  stu_num = scanner.nextInt(); stu_num scanner.nextInt() scanner.nextInt scanner if( stu_num == 0 ){
				break;
			} stu_num == 0 stu_num 0 {
				break;
			} break; double stu[] = new double[stu_num]; stu new double[stu_num] stu_num sum = 0 sum 0 dev_sum = 0 dev_sum 0 dev_w = 0 dev_w 0 for( int i = 0; i < stu_num ; i ++ ){
				stu[i] = scanner.nextDouble();
				sum += stu[i];
			} int i = 0; int i = 0; i 0 i < stu_num i stu_num i ++ i ++ i {
				stu[i] = scanner.nextDouble();
				sum += stu[i];
			} {
				stu[i] = scanner.nextDouble();
				sum += stu[i];
			} stu[i] = scanner.nextDouble() stu[i] stu i scanner.nextDouble() scanner.nextDouble scanner sum += stu[i] sum stu[i] stu i ave = sum / stu_num ave sum / stu_num sum stu_num for( int i = 0; i < stu_num ; i ++ ){
				dev = ave - stu[i];
				dev_w = dev * dev;
				dev_sum += dev_w;
			} int i = 0; int i = 0; i 0 i < stu_num i stu_num i ++ i ++ i {
				dev = ave - stu[i];
				dev_w = dev * dev;
				dev_sum += dev_w;
			} {
				dev = ave - stu[i];
				dev_w = dev * dev;
				dev_sum += dev_w;
			} dev = ave - stu[i] dev ave - stu[i] ave stu[i] stu i dev_w = dev * dev dev_w dev * dev dev dev dev_sum += dev_w dev_sum dev_w if(dev_sum != 0) {
				var = dev_sum / stu_num;		//分散
			}else {
				var = 0;
			} dev_sum != 0 dev_sum 0 {
				var = dev_sum / stu_num;		//分散
			} var = dev_sum / stu_num var dev_sum / stu_num dev_sum stu_num {
				var = 0;
			} var = 0 var 0 sta = Math.sqrt(var) sta Math.sqrt(var) Math.sqrt Math var System.out.println(sta) System.out.println System.out System System.out sta scanner.close() scanner.close scanner String args[] args
import java.util.Scanner;

class Main {
	public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);
		double area = 0.f;
		double sum;
		double sta;
		double dev;
		double dev_w;
		double dev_sum;
		double ave;
		double var;
		boolean Judge = true;
		
		while(Judge){
			int  stu_num = scanner.nextInt();	//学生数
			if( stu_num == 0 ){
				break;
			}
			double stu[] = new double[stu_num];
			sum = 0;
			dev_sum = 0;
			dev_w = 0;
			
			//点数入れる処理
			for( int i = 0; i < stu_num ; i ++ ){
				stu[i] = scanner.nextDouble();
				sum += stu[i];
			}
			ave = sum / stu_num;		//平均
			
			//偏差を求めて2乗
			for( int i = 0; i < stu_num ; i ++ ){
				dev = ave - stu[i];
				dev_w = dev * dev;
				dev_sum += dev_w;
			}
			
			if(dev_sum != 0) {
				var = dev_sum / stu_num;		//分散
			}else {
				var = 0;
			}
			
			sta = Math.sqrt(var);
		
			System.out.println(sta);
		
		}
		
		scanner.close();
	}
}


