import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        while (sc.hasNext()) {
            int i = 0;
            double m = 0, sum = 0, a = 0, b = 0;
            double[] rem;

            int n = sc.nextInt();
            if(n==0)
                break;

            rem = new double[n];
            
            for (i = 0; i < n; i++) {
                int num = sc.nextInt();
                rem[i] = num;
                sum += num;
            }

            m = sum / n;

            for (i = 0; i < n; i++) {
                b += (rem[i] - m) * (rem[i] - m);
            }
            a = Math.sqrt(b / n);

            System.out.println(a);
        }
    }
}
 import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        while (sc.hasNext()) {
            int i = 0;
            double m = 0, sum = 0, a = 0, b = 0;
            double[] rem;

            int n = sc.nextInt();
            if(n==0)
                break;

            rem = new double[n];
            
            for (i = 0; i < n; i++) {
                int num = sc.nextInt();
                rem[i] = num;
                sum += num;
            }

            m = sum / n;

            for (i = 0; i < n; i++) {
                b += (rem[i] - m) * (rem[i] - m);
            }
            a = Math.sqrt(b / n);

            System.out.println(a);
        }
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        while (sc.hasNext()) {
            int i = 0;
            double m = 0, sum = 0, a = 0, b = 0;
            double[] rem;

            int n = sc.nextInt();
            if(n==0)
                break;

            rem = new double[n];
            
            for (i = 0; i < n; i++) {
                int num = sc.nextInt();
                rem[i] = num;
                sum += num;
            }

            m = sum / n;

            for (i = 0; i < n; i++) {
                b += (rem[i] - m) * (rem[i] - m);
            }
            a = Math.sqrt(b / n);

            System.out.println(a);
        }
    } main {
        Scanner sc = new Scanner(System.in);

        while (sc.hasNext()) {
            int i = 0;
            double m = 0, sum = 0, a = 0, b = 0;
            double[] rem;

            int n = sc.nextInt();
            if(n==0)
                break;

            rem = new double[n];
            
            for (i = 0; i < n; i++) {
                int num = sc.nextInt();
                rem[i] = num;
                sum += num;
            }

            m = sum / n;

            for (i = 0; i < n; i++) {
                b += (rem[i] - m) * (rem[i] - m);
            }
            a = Math.sqrt(b / n);

            System.out.println(a);
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) while (sc.hasNext()) {
            int i = 0;
            double m = 0, sum = 0, a = 0, b = 0;
            double[] rem;

            int n = sc.nextInt();
            if(n==0)
                break;

            rem = new double[n];
            
            for (i = 0; i < n; i++) {
                int num = sc.nextInt();
                rem[i] = num;
                sum += num;
            }

            m = sum / n;

            for (i = 0; i < n; i++) {
                b += (rem[i] - m) * (rem[i] - m);
            }
            a = Math.sqrt(b / n);

            System.out.println(a);
        } sc.hasNext() sc.hasNext sc {
            int i = 0;
            double m = 0, sum = 0, a = 0, b = 0;
            double[] rem;

            int n = sc.nextInt();
            if(n==0)
                break;

            rem = new double[n];
            
            for (i = 0; i < n; i++) {
                int num = sc.nextInt();
                rem[i] = num;
                sum += num;
            }

            m = sum / n;

            for (i = 0; i < n; i++) {
                b += (rem[i] - m) * (rem[i] - m);
            }
            a = Math.sqrt(b / n);

            System.out.println(a);
        } int i = 0; i 0 double m = 0 m 0 sum = 0 sum 0 a = 0 a 0 b = 0; b 0 double[] rem; rem int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc if(n==0)
                break; n==0 n 0 break; rem = new double[n] rem new double[n] n for (i = 0; i < n; i++) {
                int num = sc.nextInt();
                rem[i] = num;
                sum += num;
            } i = 0; i = 0 i 0 i < n i n i++ i++ i {
                int num = sc.nextInt();
                rem[i] = num;
                sum += num;
            } {
                int num = sc.nextInt();
                rem[i] = num;
                sum += num;
            } int num = sc.nextInt(); num sc.nextInt() sc.nextInt sc rem[i] = num rem[i] rem i num sum += num sum num m = sum / n m sum / n sum n for (i = 0; i < n; i++) {
                b += (rem[i] - m) * (rem[i] - m);
            } i = 0; i = 0 i 0 i < n i n i++ i++ i {
                b += (rem[i] - m) * (rem[i] - m);
            } {
                b += (rem[i] - m) * (rem[i] - m);
            } b += (rem[i] - m) * (rem[i] - m) b (rem[i] - m) * (rem[i] - m) (rem[i] - m) rem[i] rem i m (rem[i] - m) rem[i] rem i m a = Math.sqrt(b / n) a Math.sqrt(b / n) Math.sqrt Math b / n b n System.out.println(a) System.out.println System.out System System.out a String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        while (sc.hasNext()) {
            int i = 0;
            double m = 0, sum = 0, a = 0, b = 0;
            double[] rem;

            int n = sc.nextInt();
            if(n==0)
                break;

            rem = new double[n];
            
            for (i = 0; i < n; i++) {
                int num = sc.nextInt();
                rem[i] = num;
                sum += num;
            }

            m = sum / n;

            for (i = 0; i < n; i++) {
                b += (rem[i] - m) * (rem[i] - m);
            }
            a = Math.sqrt(b / n);

            System.out.println(a);
        }
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        while (sc.hasNext()) {
            int i = 0;
            double m = 0, sum = 0, a = 0, b = 0;
            double[] rem;

            int n = sc.nextInt();
            if(n==0)
                break;

            rem = new double[n];
            
            for (i = 0; i < n; i++) {
                int num = sc.nextInt();
                rem[i] = num;
                sum += num;
            }

            m = sum / n;

            for (i = 0; i < n; i++) {
                b += (rem[i] - m) * (rem[i] - m);
            }
            a = Math.sqrt(b / n);

            System.out.println(a);
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        while (sc.hasNext()) {
            int i = 0;
            double m = 0, sum = 0, a = 0, b = 0;
            double[] rem;

            int n = sc.nextInt();
            if(n==0)
                break;

            rem = new double[n];
            
            for (i = 0; i < n; i++) {
                int num = sc.nextInt();
                rem[i] = num;
                sum += num;
            }

            m = sum / n;

            for (i = 0; i < n; i++) {
                b += (rem[i] - m) * (rem[i] - m);
            }
            a = Math.sqrt(b / n);

            System.out.println(a);
        }
    }
}

