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

                    double sum1 = 0, sum2 = 0;
                    for (int i = 0; i < scores.length; i++) {
                        sum1 += scores[i];
                    }
                    average = sum1 / scores.length;
                    for (int i = 0; i < scores.length; i++) {
                        sum2 += Math.pow(scores[i] - average, 2);
                    }
                    variance = sum2 / scores.length;
                    System.out.println(Math.sqrt(variance));
                }
            }
        }
    }
 
 import java.util.Scanner; Scanner java.util public class Main{
        public static void main(String[] args) {
            try (Scanner sc = new Scanner(System.in)) {
                while (true) {
                    int n = sc.nextInt();
                    if (n == 0) {
                        break;
                    }
                    int[] scores = new int[n];
                    for (int i = 0; i < scores.length; i++) {
                        scores[i] = sc.nextInt();
                    }
                    double average = 0, variance = 0;

                    double sum1 = 0, sum2 = 0;
                    for (int i = 0; i < scores.length; i++) {
                        sum1 += scores[i];
                    }
                    average = sum1 / scores.length;
                    for (int i = 0; i < scores.length; i++) {
                        sum2 += Math.pow(scores[i] - average, 2);
                    }
                    variance = sum2 / scores.length;
                    System.out.println(Math.sqrt(variance));
                }
            }
        }
    } Main public static void main(String[] args) {
            try (Scanner sc = new Scanner(System.in)) {
                while (true) {
                    int n = sc.nextInt();
                    if (n == 0) {
                        break;
                    }
                    int[] scores = new int[n];
                    for (int i = 0; i < scores.length; i++) {
                        scores[i] = sc.nextInt();
                    }
                    double average = 0, variance = 0;

                    double sum1 = 0, sum2 = 0;
                    for (int i = 0; i < scores.length; i++) {
                        sum1 += scores[i];
                    }
                    average = sum1 / scores.length;
                    for (int i = 0; i < scores.length; i++) {
                        sum2 += Math.pow(scores[i] - average, 2);
                    }
                    variance = sum2 / scores.length;
                    System.out.println(Math.sqrt(variance));
                }
            }
        } main {
            try (Scanner sc = new Scanner(System.in)) {
                while (true) {
                    int n = sc.nextInt();
                    if (n == 0) {
                        break;
                    }
                    int[] scores = new int[n];
                    for (int i = 0; i < scores.length; i++) {
                        scores[i] = sc.nextInt();
                    }
                    double average = 0, variance = 0;

                    double sum1 = 0, sum2 = 0;
                    for (int i = 0; i < scores.length; i++) {
                        sum1 += scores[i];
                    }
                    average = sum1 / scores.length;
                    for (int i = 0; i < scores.length; i++) {
                        sum2 += Math.pow(scores[i] - average, 2);
                    }
                    variance = sum2 / scores.length;
                    System.out.println(Math.sqrt(variance));
                }
            }
        } try (Scanner sc = new Scanner(System.in)) {
                while (true) {
                    int n = sc.nextInt();
                    if (n == 0) {
                        break;
                    }
                    int[] scores = new int[n];
                    for (int i = 0; i < scores.length; i++) {
                        scores[i] = sc.nextInt();
                    }
                    double average = 0, variance = 0;

                    double sum1 = 0, sum2 = 0;
                    for (int i = 0; i < scores.length; i++) {
                        sum1 += scores[i];
                    }
                    average = sum1 / scores.length;
                    for (int i = 0; i < scores.length; i++) {
                        sum2 += Math.pow(scores[i] - average, 2);
                    }
                    variance = sum2 / scores.length;
                    System.out.println(Math.sqrt(variance));
                }
            } {
                while (true) {
                    int n = sc.nextInt();
                    if (n == 0) {
                        break;
                    }
                    int[] scores = new int[n];
                    for (int i = 0; i < scores.length; i++) {
                        scores[i] = sc.nextInt();
                    }
                    double average = 0, variance = 0;

                    double sum1 = 0, sum2 = 0;
                    for (int i = 0; i < scores.length; i++) {
                        sum1 += scores[i];
                    }
                    average = sum1 / scores.length;
                    for (int i = 0; i < scores.length; i++) {
                        sum2 += Math.pow(scores[i] - average, 2);
                    }
                    variance = sum2 / scores.length;
                    System.out.println(Math.sqrt(variance));
                }
            } Scanner sc = new Scanner(System.in) Scanner sc = new Scanner(System.in) new Scanner(System.in) while (true) {
                    int n = sc.nextInt();
                    if (n == 0) {
                        break;
                    }
                    int[] scores = new int[n];
                    for (int i = 0; i < scores.length; i++) {
                        scores[i] = sc.nextInt();
                    }
                    double average = 0, variance = 0;

                    double sum1 = 0, sum2 = 0;
                    for (int i = 0; i < scores.length; i++) {
                        sum1 += scores[i];
                    }
                    average = sum1 / scores.length;
                    for (int i = 0; i < scores.length; i++) {
                        sum2 += Math.pow(scores[i] - average, 2);
                    }
                    variance = sum2 / scores.length;
                    System.out.println(Math.sqrt(variance));
                } true {
                    int n = sc.nextInt();
                    if (n == 0) {
                        break;
                    }
                    int[] scores = new int[n];
                    for (int i = 0; i < scores.length; i++) {
                        scores[i] = sc.nextInt();
                    }
                    double average = 0, variance = 0;

                    double sum1 = 0, sum2 = 0;
                    for (int i = 0; i < scores.length; i++) {
                        sum1 += scores[i];
                    }
                    average = sum1 / scores.length;
                    for (int i = 0; i < scores.length; i++) {
                        sum2 += Math.pow(scores[i] - average, 2);
                    }
                    variance = sum2 / scores.length;
                    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 for (int i = 0; i < scores.length; i++) {
                        scores[i] = sc.nextInt();
                    } int i = 0; int i = 0; i 0 i < scores.length i scores.length scores scores.length i++ i++ i {
                        scores[i] = sc.nextInt();
                    } {
                        scores[i] = sc.nextInt();
                    } scores[i] = sc.nextInt() scores[i] scores i sc.nextInt() sc.nextInt sc double average = 0 average 0 variance = 0; variance 0 double sum1 = 0 sum1 0 sum2 = 0; sum2 0 for (int i = 0; i < scores.length; i++) {
                        sum1 += scores[i];
                    } int i = 0; int i = 0; i 0 i < scores.length i scores.length scores scores.length i++ i++ i {
                        sum1 += scores[i];
                    } {
                        sum1 += scores[i];
                    } sum1 += scores[i] sum1 scores[i] scores i average = sum1 / scores.length average sum1 / scores.length sum1 scores.length scores scores.length for (int i = 0; i < scores.length; i++) {
                        sum2 += Math.pow(scores[i] - average, 2);
                    } int i = 0; int i = 0; i 0 i < scores.length i scores.length scores scores.length i++ i++ i {
                        sum2 += Math.pow(scores[i] - average, 2);
                    } {
                        sum2 += Math.pow(scores[i] - average, 2);
                    } sum2 += Math.pow(scores[i] - average, 2) sum2 Math.pow(scores[i] - average, 2) Math.pow Math scores[i] - average scores[i] scores i average 2 variance = sum2 / scores.length variance sum2 / scores.length sum2 scores.length scores scores.length 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) {
            try (Scanner sc = new Scanner(System.in)) {
                while (true) {
                    int n = sc.nextInt();
                    if (n == 0) {
                        break;
                    }
                    int[] scores = new int[n];
                    for (int i = 0; i < scores.length; i++) {
                        scores[i] = sc.nextInt();
                    }
                    double average = 0, variance = 0;

                    double sum1 = 0, sum2 = 0;
                    for (int i = 0; i < scores.length; i++) {
                        sum1 += scores[i];
                    }
                    average = sum1 / scores.length;
                    for (int i = 0; i < scores.length; i++) {
                        sum2 += Math.pow(scores[i] - average, 2);
                    }
                    variance = sum2 / scores.length;
                    System.out.println(Math.sqrt(variance));
                }
            }
        }
    } public class Main{
        public static void main(String[] args) {
            try (Scanner sc = new Scanner(System.in)) {
                while (true) {
                    int n = sc.nextInt();
                    if (n == 0) {
                        break;
                    }
                    int[] scores = new int[n];
                    for (int i = 0; i < scores.length; i++) {
                        scores[i] = sc.nextInt();
                    }
                    double average = 0, variance = 0;

                    double sum1 = 0, sum2 = 0;
                    for (int i = 0; i < scores.length; i++) {
                        sum1 += scores[i];
                    }
                    average = sum1 / scores.length;
                    for (int i = 0; i < scores.length; i++) {
                        sum2 += Math.pow(scores[i] - average, 2);
                    }
                    variance = sum2 / scores.length;
                    System.out.println(Math.sqrt(variance));
                }
            }
        }
    } Main
 import java.util.Scanner;
    public class Main{
        public static void main(String[] args) {
            try (Scanner sc = new Scanner(System.in)) {
                while (true) {
                    int n = sc.nextInt();
                    if (n == 0) {
                        break;
                    }
                    int[] scores = new int[n];
                    for (int i = 0; i < scores.length; i++) {
                        scores[i] = sc.nextInt();
                    }
                    double average = 0, variance = 0;

                    double sum1 = 0, sum2 = 0;
                    for (int i = 0; i < scores.length; i++) {
                        sum1 += scores[i];
                    }
                    average = sum1 / scores.length;
                    for (int i = 0; i < scores.length; i++) {
                        sum2 += Math.pow(scores[i] - average, 2);
                    }
                    variance = sum2 / scores.length;
                    System.out.println(Math.sqrt(variance));
                }
            }
        }
    }
 

