import java.util.Scanner;

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

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