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