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

import static java.lang.Math.*;
import static java.util.Arrays.*;
import static java.util.Collections.*;
import static java.util.Comparator.*;

public class Main {
    FastScanner in;
    PrintWriter out;
    boolean multitests = false;
    long mod = (long) 1e9 + 7; // 998_244_353L || (long) 1e9 + 9
    ArrayList<Integer>[] graph;
    ArrayList<GraphPair>[] weightedGraph;

    private void solve() throws IOException {
        // solveA();
        solveB();
        // solveC();
        // solveD();
        // solveE();
        // solveF();
    }

    private void solveA() throws IOException {
        int n = in.nextInt(), x = in.nextInt(), y = in.nextInt();
        int[] a = in.nextIntArray(n);
        for (int d = 0; d < n; d++) {
            boolean ok = true;
            for (int j = max(0, d - x); j < d; j++)
                ok &= a[d] < a[j];
            for (int j = min(n - 1, d + y); j > d; j--)
                ok &= a[d] < a[j];
            if (ok) {
                out.println(d + 1);
                return;
            }
        }
    }

    private void solveB() throws IOException {
        long H = in.nextLong(), L = in.nextLong();
        out.println((H * H + L * L) / 2.0 / H - H);
    }

    private void solveC() throws IOException {

    }

    private void solveD() throws IOException {

    }

    private void solveE() throws IOException {

    }

    private void solveF() throws IOException {

    }

    void shuffleInt(int[] a) {
        Random random = new Random();
        for (int i = a.length - 1; i > 0; i--) {
            int j = random.nextInt(i + 1);
            int swap = a[j];
            a[j] = a[i];
            a[i] = swap;
        }
    }

    void shuffleLong(long[] a) {
        Random random = new Random();
        for (int i = a.length - 1; i > 0; i--) {
            int j = random.nextInt(i + 1);
            long swap = a[j];
            a[j] = a[i];
            a[i] = swap;
        }
    }

    void reverseInt(int[] a) {
        for (int i = 0, j = a.length - 1; i < j; i++, j--) {
            int swap = a[i];
            a[i] = a[j];
            a[j] = swap;
        }
    }

    void reverseLong(long[] a) {
        for (int i = 0, j = a.length - 1; i < j; i++, j--) {
            long swap = a[i];
            a[i] = a[j];
            a[j] = swap;
        }
    }

    int maxInt(int[] a) {
        int max = a[0];
        for (int i = 1; i < a.length; i++)
            if (max < a[i])
                max = a[i];
        return max;
    }

    long maxLong(long[] a) {
        long max = a[0];
        for (int i = 1; i < a.length; i++)
            if (max < a[i])
                max = a[i];
        return max;
    }

    int minInt(int[] a) {
        int min = a[0];
        for (int i = 1; i < a.length; i++)
            if (min > a[i])
                min = a[i];
        return min;
    }

    long minLong(long[] a) {
        long min = a[0];
        for (int i = 1; i < a.length; i++)
            if (min > a[i])
                min = a[i];
        return min;
    }

    long sumInt(int[] a) {
        long s = 0;
        for (int i = 0; i < a.length; i++)
            s += a[i];
        return s;
    }

    long sumLong(long[] a) {
        long s = 0;
        for (int i = 0; i < a.length; i++)
            s += a[i];
        return s;
    }

    long gcd(long a, long b) {
        return b == 0 ? a : gcd(b, a % b);
    }

    long binpowmod(long a, long n) {
        long res = 1;
        a %= mod;
        n %= mod - 1;
        while (n > 0) {
            if (n % 2 == 1)
                res = (res * a) % mod;
            a = (a * a) % mod;
            n /= 2;
        }
        return res;
    }

    class GraphPair implements Comparable<GraphPair> {
        int v;
        long w;

        GraphPair(int v, long w) {
            this.v = v;
            this.w = w;
        }

        public int compareTo(GraphPair o) {
            return w != o.w ? Long.compare(w, o.w) : Integer.compare(v, o.v);
        }
    }

    ArrayList<Integer>[] createGraph(int n) throws IOException {
        ArrayList<Integer>[] graph = new ArrayList[n];
        for (int i = 0; i < n; i++)
            graph[i] = new ArrayList<>();
        return graph;
    }

    ArrayList<GraphPair>[] createWeightedGraph(int n) throws IOException {
        ArrayList<GraphPair>[] graph = new ArrayList[n];
        for (int i = 0; i < n; i++)
            graph[i] = new ArrayList<>();
        return graph;
    }

    class FastScanner {
        StringTokenizer st;
        BufferedReader br;

        FastScanner(InputStream s) {
            br = new BufferedReader(new InputStreamReader(s), 32768);
        }

        String next() throws IOException {
            while (st == null || !st.hasMoreTokens())
                st = new StringTokenizer(br.readLine());
            return st.nextToken();
        }

        boolean hasNext() throws IOException {
            return br.ready() || (st != null && st.hasMoreTokens());
        }

        int nextInt() throws IOException {
            return Integer.parseInt(next());
        }

        int[] nextIntArray(int n) throws IOException {
            int[] a = new int[n];
            for (int i = 0; i < n; i++)
                a[i] = in.nextInt();
            return a;
        }

        int[][] nextIntTable(int n, int m) throws IOException {
            int[][] a = new int[n][m];
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++)
                    a[i][j] = in.nextInt();
            return a;
        }

        long nextLong() throws IOException {
            return Long.parseLong(next());
        }

        long[] nextLongArray(int n) throws IOException {
            long[] a = new long[n];
            for (int i = 0; i < n; i++)
                a[i] = in.nextLong();
            return a;
        }

        long[][] nextLongTable(int n, int m) throws IOException {
            long[][] a = new long[n][m];
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++)
                    a[i][j] = in.nextLong();
            return a;
        }

        ArrayList<Integer>[] nextGraph(int n, int m, boolean directed) throws IOException {
            ArrayList<Integer>[] graph = createGraph(n);
            for (int i = 0; i < m; i++) {
                int v = in.nextInt() - 1, u = in.nextInt() - 1;
                graph[v].add(u);
                if (!directed)
                    graph[u].add(v);
            }
            return graph;
        }

        ArrayList<GraphPair>[] nextWeightedGraph(int n, int m, boolean directed) throws IOException {
            ArrayList<GraphPair>[] graph = createWeightedGraph(n);
            for (int i = 0; i < m; i++) {
                int v = in.nextInt() - 1, u = in.nextInt() - 1;
                long w = in.nextLong();
                graph[v].add(new GraphPair(u, w));
                if (!directed)
                    graph[u].add(new GraphPair(v, w));
            }
            return graph;
        }

        double nextDouble() throws IOException {
            return Double.parseDouble(next());
        }

        String nextLine() throws IOException {
            return br.readLine();
        }

        boolean hasNextLine() throws IOException {
            return br.ready();
        }
    }

    private void run() throws IOException {
        in = new FastScanner(System.in); // new FastScanner(new FileInputStream(".in"));
        out = new PrintWriter(System.out); // new PrintWriter(new FileOutputStream(".out"));

        for (int t = multitests ? in.nextInt() : 1; t-- > 0; )
            solve();

        out.flush();
        out.close();
    }

    public static void main(String[] args) throws IOException {
        new Main().run();
    }
}