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 sum = 0, average = 0, variance = 0, x = 0, xsum = 0; 
            for (int j = 0; j < scores.length; j++) {
                sum+=scores[j];
            }
            average = sum / scores.length;
            for (int k = 0; k < scores.length; k++) {
                x=scores[k]-average;
                xsum+=x*x;
            }
            variance = xsum / 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 sum = 0, average = 0, variance = 0, x = 0, xsum = 0; 
            for (int j = 0; j < scores.length; j++) {
                sum+=scores[j];
            }
            average = sum / scores.length;
            for (int k = 0; k < scores.length; k++) {
                x=scores[k]-average;
                xsum+=x*x;
            }
            variance = xsum / 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 sum = 0, average = 0, variance = 0, x = 0, xsum = 0; 
            for (int j = 0; j < scores.length; j++) {
                sum+=scores[j];
            }
            average = sum / scores.length;
            for (int k = 0; k < scores.length; k++) {
                x=scores[k]-average;
                xsum+=x*x;
            }
            variance = xsum / 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 sum = 0, average = 0, variance = 0, x = 0, xsum = 0; 
            for (int j = 0; j < scores.length; j++) {
                sum+=scores[j];
            }
            average = sum / scores.length;
            for (int k = 0; k < scores.length; k++) {
                x=scores[k]-average;
                xsum+=x*x;
            }
            variance = xsum / 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 sum = 0, average = 0, variance = 0, x = 0, xsum = 0; 
            for (int j = 0; j < scores.length; j++) {
                sum+=scores[j];
            }
            average = sum / scores.length;
            for (int k = 0; k < scores.length; k++) {
                x=scores[k]-average;
                xsum+=x*x;
            }
            variance = xsum / 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 sum = 0, average = 0, variance = 0, x = 0, xsum = 0; 
            for (int j = 0; j < scores.length; j++) {
                sum+=scores[j];
            }
            average = sum / scores.length;
            for (int k = 0; k < scores.length; k++) {
                x=scores[k]-average;
                xsum+=x*x;
            }
            variance = xsum / 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 sum = 0, average = 0, variance = 0, x = 0, xsum = 0; 
            for (int j = 0; j < scores.length; j++) {
                sum+=scores[j];
            }
            average = sum / scores.length;
            for (int k = 0; k < scores.length; k++) {
                x=scores[k]-average;
                xsum+=x*x;
            }
            variance = xsum / 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 sum = 0, average = 0, variance = 0, x = 0, xsum = 0; 
            for (int j = 0; j < scores.length; j++) {
                sum+=scores[j];
            }
            average = sum / scores.length;
            for (int k = 0; k < scores.length; k++) {
                x=scores[k]-average;
                xsum+=x*x;
            }
            variance = xsum / 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 sum = 0 sum 0 average = 0 average 0 variance = 0 variance 0 x = 0 x 0 xsum = 0; xsum 0 for (int j = 0; j < scores.length; j++) {
                sum+=scores[j];
            } int j = 0; int j = 0; j 0 j < scores.length j scores.length scores scores.length j++ j++ j {
                sum+=scores[j];
            } {
                sum+=scores[j];
            } sum+=scores[j] sum scores[j] scores j average = sum / scores.length average sum / scores.length sum scores.length scores scores.length for (int k = 0; k < scores.length; k++) {
                x=scores[k]-average;
                xsum+=x*x;
            } int k = 0; int k = 0; k 0 k < scores.length k scores.length scores scores.length k++ k++ k {
                x=scores[k]-average;
                xsum+=x*x;
            } {
                x=scores[k]-average;
                xsum+=x*x;
            } x=scores[k]-average x scores[k]-average scores[k] scores k average xsum+=x*x xsum x*x x x variance = xsum / scores.length variance xsum / scores.length xsum 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 sum = 0, average = 0, variance = 0, x = 0, xsum = 0; 
            for (int j = 0; j < scores.length; j++) {
                sum+=scores[j];
            }
            average = sum / scores.length;
            for (int k = 0; k < scores.length; k++) {
                x=scores[k]-average;
                xsum+=x*x;
            }
            variance = xsum / 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 sum = 0, average = 0, variance = 0, x = 0, xsum = 0; 
            for (int j = 0; j < scores.length; j++) {
                sum+=scores[j];
            }
            average = sum / scores.length;
            for (int k = 0; k < scores.length; k++) {
                x=scores[k]-average;
                xsum+=x*x;
            }
            variance = xsum / 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 sum = 0, average = 0, variance = 0, x = 0, xsum = 0; 
            for (int j = 0; j < scores.length; j++) {
                sum+=scores[j];
            }
            average = sum / scores.length;
            for (int k = 0; k < scores.length; k++) {
                x=scores[k]-average;
                xsum+=x*x;
            }
            variance = xsum / scores.length;
            System.out.println(Math.sqrt(variance)); 
            } 
        } 
    } 
}

