Problem: You are given a sequence of n integers a1, a2, ..., an. 

Determine a real number x such that the weakness of the sequence a1 - x, a2 - x, ..., an - x is as small as possible.

The weakness of a sequence is defined as the maximum value of the poorness over all segments (contiguous subsequences) of a sequence.

The poorness of a segment is defined as the absolute value of sum of the elements of segment.

Input

The first line contains one integer n (1 ≤ n ≤ 200 000), the length of a sequence.

The second line contains n integers a1, a2, ..., an (|ai| ≤ 10 000).

Output

Output a real number denoting the minimum possible weakness of a1 - x, a2 - x, ..., an - x. Your answer will be considered correct if its relative or absolute error doesn't exceed 10 - 6.

Examples

Input

3
1 2 3


Output

1.000000000000000


Input

4
1 2 3 4


Output

2.000000000000000


Input

10
1 10 2 9 3 8 4 7 5 6


Output

4.500000000000000

Note

For the first case, the optimal value of x is 2 so the sequence becomes  - 1, 0, 1 and the max poorness occurs at the segment "-1" or segment "1". The poorness value (answer) equals to 1 in this case. 

For the second sample the optimal value of x is 2.5 so the sequence becomes  - 1.5, - 0.5, 0.5, 1.5 and the max poorness occurs on segment "-1.5 -0.5" or "0.5 1.5". The poorness value (answer) equals to 2 in this case.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;
import java.math.*;

public class A implements Runnable {

    public void run() {
        long startTime = System.nanoTime();

        int n = nextInt();
        int[] a = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = nextInt();
        }
        double minx = -1e4, maxx = 1e4, res = 0;
        for (int iter = 0; iter < 100; iter++) {

            double t = (minx + maxx) / 2;

            double gmin = 1e9, gmax = -1e9;
            double min = 1, max = -1;
            for (int i = 0; i < n; i++) {
                double v = a[i] - t;
                min = Math.min(min + v, v);
                max = Math.max(max + v, v);
                gmin = Math.min(gmin, min);
                gmax = Math.max(gmax, max);
            }
            if (-gmin < gmax) {
                minx = t;
            } else {
                maxx = t;
            }
            res = gmax;
        }
        println(res);

        if (fileIOMode) {
            System.out.println((System.nanoTime() - startTime) / 1e9);
        }
        out.close();
    }

    //-----------------------------------------------------------------------------------

    private static boolean fileIOMode;
    private static BufferedReader in;
    private static PrintWriter out;
    private static StringTokenizer tokenizer;

    public static void main(String[] args) throws Exception {
        fileIOMode = args.length > 0 && args[0].equals("!");
        if (fileIOMode) {
            in = new BufferedReader(new FileReader("a.in"));
            out = new PrintWriter("a.out");
        } else {
            in = new BufferedReader(new InputStreamReader(System.in));
            out = new PrintWriter(System.out);
        }
        tokenizer = new StringTokenizer("");

        new Thread(new A()).start();
    }

    private static String nextLine() {
        try {
            return in.readLine();
        } catch (IOException e) {
            return null;
        }
    }

    private static String nextToken() {
        while (!tokenizer.hasMoreTokens()) {
            tokenizer = new StringTokenizer(nextLine());
        }
        return tokenizer.nextToken();
    }

    private static int nextInt() {
        return Integer.parseInt(nextToken());
    }

    private static long nextLong() {
        return Long.parseLong(nextToken());
    }

    private static double nextDouble() {
        return Double.parseDouble(nextToken());
    }

    private static BigInteger nextBigInteger() {
        return new BigInteger(nextToken());
    }

    private static void print(Object o) {
        if (fileIOMode) {
            System.out.print(o);
        }
        out.print(o);
    }

    private static void println(Object o) {
        if (fileIOMode) {
            System.out.println(o);
        }
        out.println(o);
    }

    private static void printf(String s, Object... o) {
        if (fileIOMode) {
            System.out.printf(s, o);
        }
        out.printf(s, o);
    }
}