import java.util.Scanner;

public class Main {
    public double calcAverage(int[] buf, int num) {
        double sum = 0;
        for (int i = 0; i < num; i++) {
            sum += (double)buf[i];
        }

        return sum/(double)num;
    }
    public double calcSD(int[] buf, int num) {
        double average = calcAverage(buf, num);
        double bunsan;
        double sum = 0.0;

        for (int i = 0; i < num; i++) {
            sum += Math.pow((double)buf[i] - average, 2.0);
        }
        bunsan = sum / (double)num;
        return Math.sqrt(bunsan);
    }

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

        while (true) {
            int num = Integer.parseInt(scan.next());
            if (num == 0) {
                break;
            }
            int[] score = new int[num];
            double sd;
            for (int i = 0; i < num; i++) {
                score[i] = Integer.parseInt(scan.next());
            }

            sd = app.calcSD(score, num);
            System.out.println(sd);
        }
    }
}
 import java.util.Scanner; Scanner java.util public class Main {
    public double calcAverage(int[] buf, int num) {
        double sum = 0;
        for (int i = 0; i < num; i++) {
            sum += (double)buf[i];
        }

        return sum/(double)num;
    }
    public double calcSD(int[] buf, int num) {
        double average = calcAverage(buf, num);
        double bunsan;
        double sum = 0.0;

        for (int i = 0; i < num; i++) {
            sum += Math.pow((double)buf[i] - average, 2.0);
        }
        bunsan = sum / (double)num;
        return Math.sqrt(bunsan);
    }

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

        while (true) {
            int num = Integer.parseInt(scan.next());
            if (num == 0) {
                break;
            }
            int[] score = new int[num];
            double sd;
            for (int i = 0; i < num; i++) {
                score[i] = Integer.parseInt(scan.next());
            }

            sd = app.calcSD(score, num);
            System.out.println(sd);
        }
    }
} Main public double calcAverage(int[] buf, int num) {
        double sum = 0;
        for (int i = 0; i < num; i++) {
            sum += (double)buf[i];
        }

        return sum/(double)num;
    } calcAverage {
        double sum = 0;
        for (int i = 0; i < num; i++) {
            sum += (double)buf[i];
        }

        return sum/(double)num;
    } double sum = 0; sum 0 for (int i = 0; i < num; i++) {
            sum += (double)buf[i];
        } int i = 0; int i = 0; i 0 i < num i num i++ i++ i {
            sum += (double)buf[i];
        } {
            sum += (double)buf[i];
        } sum += (double)buf[i] sum (double)buf[i] buf i return sum/(double)num; sum/(double)num sum (double)num int[] buf buf int num num public double calcSD(int[] buf, int num) {
        double average = calcAverage(buf, num);
        double bunsan;
        double sum = 0.0;

        for (int i = 0; i < num; i++) {
            sum += Math.pow((double)buf[i] - average, 2.0);
        }
        bunsan = sum / (double)num;
        return Math.sqrt(bunsan);
    } calcSD {
        double average = calcAverage(buf, num);
        double bunsan;
        double sum = 0.0;

        for (int i = 0; i < num; i++) {
            sum += Math.pow((double)buf[i] - average, 2.0);
        }
        bunsan = sum / (double)num;
        return Math.sqrt(bunsan);
    } double average = calcAverage(buf, num); average calcAverage(buf, num) calcAverage buf num double bunsan; bunsan double sum = 0.0; sum 0.0 for (int i = 0; i < num; i++) {
            sum += Math.pow((double)buf[i] - average, 2.0);
        } int i = 0; int i = 0; i 0 i < num i num i++ i++ i {
            sum += Math.pow((double)buf[i] - average, 2.0);
        } {
            sum += Math.pow((double)buf[i] - average, 2.0);
        } sum += Math.pow((double)buf[i] - average, 2.0) sum Math.pow((double)buf[i] - average, 2.0) Math.pow Math (double)buf[i] - average (double)buf[i] buf i average 2.0 bunsan = sum / (double)num bunsan sum / (double)num sum (double)num return Math.sqrt(bunsan); Math.sqrt(bunsan) Math.sqrt Math bunsan int[] buf buf int num num public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        Main app = new Main();

        while (true) {
            int num = Integer.parseInt(scan.next());
            if (num == 0) {
                break;
            }
            int[] score = new int[num];
            double sd;
            for (int i = 0; i < num; i++) {
                score[i] = Integer.parseInt(scan.next());
            }

            sd = app.calcSD(score, num);
            System.out.println(sd);
        }
    } main {
        Scanner scan = new Scanner(System.in);
        Main app = new Main();

        while (true) {
            int num = Integer.parseInt(scan.next());
            if (num == 0) {
                break;
            }
            int[] score = new int[num];
            double sd;
            for (int i = 0; i < num; i++) {
                score[i] = Integer.parseInt(scan.next());
            }

            sd = app.calcSD(score, num);
            System.out.println(sd);
        }
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) Main app = new Main(); app new Main() while (true) {
            int num = Integer.parseInt(scan.next());
            if (num == 0) {
                break;
            }
            int[] score = new int[num];
            double sd;
            for (int i = 0; i < num; i++) {
                score[i] = Integer.parseInt(scan.next());
            }

            sd = app.calcSD(score, num);
            System.out.println(sd);
        } true {
            int num = Integer.parseInt(scan.next());
            if (num == 0) {
                break;
            }
            int[] score = new int[num];
            double sd;
            for (int i = 0; i < num; i++) {
                score[i] = Integer.parseInt(scan.next());
            }

            sd = app.calcSD(score, num);
            System.out.println(sd);
        } int num = Integer.parseInt(scan.next()); num Integer.parseInt(scan.next()) Integer.parseInt Integer scan.next() scan.next scan if (num == 0) {
                break;
            } num == 0 num 0 {
                break;
            } break; int[] score = new int[num]; score new int[num] num double sd; sd for (int i = 0; i < num; i++) {
                score[i] = Integer.parseInt(scan.next());
            } int i = 0; int i = 0; i 0 i < num i num i++ i++ i {
                score[i] = Integer.parseInt(scan.next());
            } {
                score[i] = Integer.parseInt(scan.next());
            } score[i] = Integer.parseInt(scan.next()) score[i] score i Integer.parseInt(scan.next()) Integer.parseInt Integer scan.next() scan.next scan sd = app.calcSD(score, num) sd app.calcSD(score, num) app.calcSD app score num System.out.println(sd) System.out.println System.out System System.out sd String[] args args public class Main {
    public double calcAverage(int[] buf, int num) {
        double sum = 0;
        for (int i = 0; i < num; i++) {
            sum += (double)buf[i];
        }

        return sum/(double)num;
    }
    public double calcSD(int[] buf, int num) {
        double average = calcAverage(buf, num);
        double bunsan;
        double sum = 0.0;

        for (int i = 0; i < num; i++) {
            sum += Math.pow((double)buf[i] - average, 2.0);
        }
        bunsan = sum / (double)num;
        return Math.sqrt(bunsan);
    }

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

        while (true) {
            int num = Integer.parseInt(scan.next());
            if (num == 0) {
                break;
            }
            int[] score = new int[num];
            double sd;
            for (int i = 0; i < num; i++) {
                score[i] = Integer.parseInt(scan.next());
            }

            sd = app.calcSD(score, num);
            System.out.println(sd);
        }
    }
} public class Main {
    public double calcAverage(int[] buf, int num) {
        double sum = 0;
        for (int i = 0; i < num; i++) {
            sum += (double)buf[i];
        }

        return sum/(double)num;
    }
    public double calcSD(int[] buf, int num) {
        double average = calcAverage(buf, num);
        double bunsan;
        double sum = 0.0;

        for (int i = 0; i < num; i++) {
            sum += Math.pow((double)buf[i] - average, 2.0);
        }
        bunsan = sum / (double)num;
        return Math.sqrt(bunsan);
    }

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

        while (true) {
            int num = Integer.parseInt(scan.next());
            if (num == 0) {
                break;
            }
            int[] score = new int[num];
            double sd;
            for (int i = 0; i < num; i++) {
                score[i] = Integer.parseInt(scan.next());
            }

            sd = app.calcSD(score, num);
            System.out.println(sd);
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public double calcAverage(int[] buf, int num) {
        double sum = 0;
        for (int i = 0; i < num; i++) {
            sum += (double)buf[i];
        }

        return sum/(double)num;
    }
    public double calcSD(int[] buf, int num) {
        double average = calcAverage(buf, num);
        double bunsan;
        double sum = 0.0;

        for (int i = 0; i < num; i++) {
            sum += Math.pow((double)buf[i] - average, 2.0);
        }
        bunsan = sum / (double)num;
        return Math.sqrt(bunsan);
    }

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

        while (true) {
            int num = Integer.parseInt(scan.next());
            if (num == 0) {
                break;
            }
            int[] score = new int[num];
            double sd;
            for (int i = 0; i < num; i++) {
                score[i] = Integer.parseInt(scan.next());
            }

            sd = app.calcSD(score, num);
            System.out.println(sd);
        }
    }
}

