import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while(true) {
		int n;
		n = sc.nextInt();
		if(n==0) {
			break;
		}
		double[] num;
		double sum = 0;
		num = new double[n];
		for(int i = 0;i<n;i++) {
			num[i] = sc.nextInt();
			sum += num[i];
		}

		double ave = sum/n;
		double sum_2 = 0;
		for(int i = 0;i<n;i++) {
			sum_2 += (num[i]-ave)*(num[i]-ave);
		}
		double bunsan = sum_2/n;
		double ans = Math.sqrt(bunsan);
		System.out.printf("%f\n",ans);
	}
		sc.close();
	}
} 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 n;
		n = sc.nextInt();
		if(n==0) {
			break;
		}
		double[] num;
		double sum = 0;
		num = new double[n];
		for(int i = 0;i<n;i++) {
			num[i] = sc.nextInt();
			sum += num[i];
		}

		double ave = sum/n;
		double sum_2 = 0;
		for(int i = 0;i<n;i++) {
			sum_2 += (num[i]-ave)*(num[i]-ave);
		}
		double bunsan = sum_2/n;
		double ans = Math.sqrt(bunsan);
		System.out.printf("%f\n",ans);
	}
		sc.close();
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while(true) {
		int n;
		n = sc.nextInt();
		if(n==0) {
			break;
		}
		double[] num;
		double sum = 0;
		num = new double[n];
		for(int i = 0;i<n;i++) {
			num[i] = sc.nextInt();
			sum += num[i];
		}

		double ave = sum/n;
		double sum_2 = 0;
		for(int i = 0;i<n;i++) {
			sum_2 += (num[i]-ave)*(num[i]-ave);
		}
		double bunsan = sum_2/n;
		double ans = Math.sqrt(bunsan);
		System.out.printf("%f\n",ans);
	}
		sc.close();
	} main {
		Scanner sc = new Scanner(System.in);
		while(true) {
		int n;
		n = sc.nextInt();
		if(n==0) {
			break;
		}
		double[] num;
		double sum = 0;
		num = new double[n];
		for(int i = 0;i<n;i++) {
			num[i] = sc.nextInt();
			sum += num[i];
		}

		double ave = sum/n;
		double sum_2 = 0;
		for(int i = 0;i<n;i++) {
			sum_2 += (num[i]-ave)*(num[i]-ave);
		}
		double bunsan = sum_2/n;
		double ans = Math.sqrt(bunsan);
		System.out.printf("%f\n",ans);
	}
		sc.close();
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) while(true) {
		int n;
		n = sc.nextInt();
		if(n==0) {
			break;
		}
		double[] num;
		double sum = 0;
		num = new double[n];
		for(int i = 0;i<n;i++) {
			num[i] = sc.nextInt();
			sum += num[i];
		}

		double ave = sum/n;
		double sum_2 = 0;
		for(int i = 0;i<n;i++) {
			sum_2 += (num[i]-ave)*(num[i]-ave);
		}
		double bunsan = sum_2/n;
		double ans = Math.sqrt(bunsan);
		System.out.printf("%f\n",ans);
	} true {
		int n;
		n = sc.nextInt();
		if(n==0) {
			break;
		}
		double[] num;
		double sum = 0;
		num = new double[n];
		for(int i = 0;i<n;i++) {
			num[i] = sc.nextInt();
			sum += num[i];
		}

		double ave = sum/n;
		double sum_2 = 0;
		for(int i = 0;i<n;i++) {
			sum_2 += (num[i]-ave)*(num[i]-ave);
		}
		double bunsan = sum_2/n;
		double ans = Math.sqrt(bunsan);
		System.out.printf("%f\n",ans);
	} int n; n n = sc.nextInt() n sc.nextInt() sc.nextInt sc if(n==0) {
			break;
		} n==0 n 0 {
			break;
		} break; double[] num; num double sum = 0; sum 0 num = new double[n] num new double[n] n for(int i = 0;i<n;i++) {
			num[i] = sc.nextInt();
			sum += num[i];
		} int i = 0; int i = 0; i 0 i<n i n i++ i++ i {
			num[i] = sc.nextInt();
			sum += num[i];
		} {
			num[i] = sc.nextInt();
			sum += num[i];
		} num[i] = sc.nextInt() num[i] num i sc.nextInt() sc.nextInt sc sum += num[i] sum num[i] num i double ave = sum/n; ave sum/n sum n double sum_2 = 0; sum_2 0 for(int i = 0;i<n;i++) {
			sum_2 += (num[i]-ave)*(num[i]-ave);
		} int i = 0; int i = 0; i 0 i<n i n i++ i++ i {
			sum_2 += (num[i]-ave)*(num[i]-ave);
		} {
			sum_2 += (num[i]-ave)*(num[i]-ave);
		} sum_2 += (num[i]-ave)*(num[i]-ave) sum_2 (num[i]-ave)*(num[i]-ave) (num[i]-ave) num[i] num i ave (num[i]-ave) num[i] num i ave double bunsan = sum_2/n; bunsan sum_2/n sum_2 n double ans = Math.sqrt(bunsan); ans Math.sqrt(bunsan) Math.sqrt Math bunsan System.out.printf("%f\n",ans) System.out.printf System.out System System.out "%f\n" ans sc.close() sc.close sc String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while(true) {
		int n;
		n = sc.nextInt();
		if(n==0) {
			break;
		}
		double[] num;
		double sum = 0;
		num = new double[n];
		for(int i = 0;i<n;i++) {
			num[i] = sc.nextInt();
			sum += num[i];
		}

		double ave = sum/n;
		double sum_2 = 0;
		for(int i = 0;i<n;i++) {
			sum_2 += (num[i]-ave)*(num[i]-ave);
		}
		double bunsan = sum_2/n;
		double ans = Math.sqrt(bunsan);
		System.out.printf("%f\n",ans);
	}
		sc.close();
	}
} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while(true) {
		int n;
		n = sc.nextInt();
		if(n==0) {
			break;
		}
		double[] num;
		double sum = 0;
		num = new double[n];
		for(int i = 0;i<n;i++) {
			num[i] = sc.nextInt();
			sum += num[i];
		}

		double ave = sum/n;
		double sum_2 = 0;
		for(int i = 0;i<n;i++) {
			sum_2 += (num[i]-ave)*(num[i]-ave);
		}
		double bunsan = sum_2/n;
		double ans = Math.sqrt(bunsan);
		System.out.printf("%f\n",ans);
	}
		sc.close();
	}
} Main
import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while(true) {
		int n;
		n = sc.nextInt();
		if(n==0) {
			break;
		}
		double[] num;
		double sum = 0;
		num = new double[n];
		for(int i = 0;i<n;i++) {
			num[i] = sc.nextInt();
			sum += num[i];
		}

		double ave = sum/n;
		double sum_2 = 0;
		for(int i = 0;i<n;i++) {
			sum_2 += (num[i]-ave)*(num[i]-ave);
		}
		double bunsan = sum_2/n;
		double ans = Math.sqrt(bunsan);
		System.out.printf("%f\n",ans);
	}
		sc.close();
	}
}
