Problem: While sailing on a boat, Inessa noticed a beautiful water lily flower above the lake's surface. She came closer and it turned out that the lily was exactly H centimeters above the water surface. Inessa grabbed the flower and sailed the distance of L centimeters. Exactly at this point the flower touched the water surface.

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Suppose that the lily grows at some point A on the lake bottom, and its stem is always a straight segment with one endpoint at point A. Also suppose that initially the flower was exactly above the point A, i.e. its stem was vertical. Can you determine the depth of the lake at point A?

Input

The only line contains two integers H and L (1 ≤ H < L ≤ 10^{6}).

Output

Print a single number — the depth of the lake at point A. The absolute or relative error should not exceed 10^{-6}.

Formally, let your answer be A, and the jury's answer be B. Your answer is accepted if and only if \frac{|A - B|}{max{(1, |B|)}} ≤ 10^{-6}.

Examples

Input


1 2


Output


1.5000000000000


Input


3 5


Output


2.6666666666667

Solution (in JAVA):

Solution:
import java.util.*;
import java.io.*;
import java.util.Map.Entry;

public class Codeforces {

    public static class SegmentTree {        // 1-based DS, OOP

        int N;            //the number of elements in the array as a power of 2 (i.e. after padding)
        int[] array, sTree, lazy;

        SegmentTree(int[] in) {
            array = in;
            N = in.length - 1;
            sTree = new int[N << 1];        //no. of nodes = 2*N - 1, we add one to cross out index zero
            lazy = new int[N << 1];
            build(1, 1, N);
        }

        void build(int node, int b, int e)    // O(n)
        {
            if (b == e)
                sTree[node] = array[b];
            else {
                int mid = b + e >> 1;
                build(node << 1, b, mid);
                build(node << 1 | 1, mid + 1, e);
                sTree[node] = Math.min(sTree[node << 1], sTree[node << 1 | 1]);
            }
        }


        void update_point(int index, int val)            // O(log n)
        {
            index += N - 1;
            sTree[index] += val;
            while (index > 1) {
                index >>= 1;
                sTree[index] = Math.min(sTree[index << 1], sTree[index << 1 | 1]);
            }
        }


        void update_range(int i, int j, int val)        // O(log n)
        {
            update_range(1, 1, N, i, j, val);
        }

        void update_range(int node, int b, int e, int i, int j, int val) {
            if (i > e || j < b)
                return;
            if (b >= i && e <= j) {
                sTree[node] += (e - b + 1) * val;
                lazy[node] += val;
            } else {
                int mid = b + e >> 1;
                propagate(node, b, mid, e);
                update_range(node << 1, b, mid, i, j, val);
                update_range(node << 1 | 1, mid + 1, e, i, j, val);
                sTree[node] = Math.min(sTree[node << 1], sTree[node << 1 | 1]);
            }

        }

        void propagate(int node, int b, int mid, int e) {
            lazy[node << 1] += lazy[node];
            lazy[node << 1 | 1] += lazy[node];
            sTree[node << 1] += (mid - b + 1) * lazy[node];
            sTree[node << 1 | 1] += (e - mid) * lazy[node];
            lazy[node] = 0;
        }

        int query(int i, int j) {
            return query(1, 1, N, i, j);
        }

        int query(int node, int b, int e, int i, int j)    // O(log n)
        {
            if (i > e || j < b)
                return Integer.MAX_VALUE;
            if (b >= i && e <= j)
                return sTree[node];
            int mid = b + e >> 1;
            propagate(node, b, mid, e);
            int q1 = query(node << 1, b, mid, i, j);
            int q2 = query(node << 1 | 1, mid + 1, e, i, j);
            return Math.min(q1, q2);

        }
    }

    static final double EPS = 1e-6;

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw = new PrintWriter(System.out);
        StringTokenizer st = new StringTokenizer(br.readLine());
        int h = Integer.parseInt(st.nextToken());
        int l = Integer.parseInt(st.nextToken());
        double b = Math.sqrt(1l * l * l + 1l * h * h);
//        pw.println(b);
        double y = Math.atan((double) l / h);
//        pw.println(y);
        double x = 2 * Math.PI - (2 * y);
//        pw.println(x);
        double a = (b * Math.sin(y)) / Math.sin(x);
//        pw.println("Sin(x) = " + Math.sin(x));
        pw.println(Math.abs(a) - h);
        pw.flush();
        pw.close();
    }
}