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
import java.io.*;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.*;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.zip.Inflater;


public class Main {
    private static AWriter writer = new AWriter(System.out);
    private static AReader reader = new AReader(System.in);
    private static final int INF=0X3F3F3F3F;
    private static int n,x,y;
    private static int a[];
    private static int tree[];
    private static long sum[];
    private static int dp[][];
    private static void built(int i,int l,int r){
        if(r==l) {
            tree[i] = a[r];
            return;
        }
        int mid=(r+l)>>1;
        built(i<<1,l,mid);
        built(i<<1|1,mid+1,r);
        tree[i]=Math.min(tree[i<<1],tree[i<<1|1]);
    }
    private static int query(int o,int l,int r,int ql,int qr){
        if(qr>=r&&l>=ql)
            return tree[o];
        int mid=(r+l)>>1;
        int op1=INF,op2=INF;
        if(ql<=mid)
            op1=query(o<<1,l,mid,ql,qr);
        if(qr>=mid+1)
            op2=query(o<<1|1,mid+1,r,ql,qr);
        return Math.min(op1,op2);
    }
    public static void main(String[] args) throws IOException {
        double a=reader.nextDouble();
        double b=reader.nextDouble();
        System.out.printf("%.13f",(a*a+b*b)/(2*a)-a);
        writer.close();
        reader.close();
    }
}

class AReader implements Closeable {
    private BufferedReader reader;
    private StringTokenizer tokenizer;
    public AReader(InputStream inputStream) {
        reader = new BufferedReader(new InputStreamReader(inputStream));
        tokenizer = new StringTokenizer("");
    }
    private String innerNextLine() {
        try {
            return reader.readLine();
        } catch (IOException ex) {
            return null;
        }
    }
    public boolean hasNext() {
        while (!tokenizer.hasMoreTokens()) {
            String nextLine = innerNextLine();
            if (nextLine == null) {
                return false;
            }
            tokenizer = new StringTokenizer(nextLine);
        }
        return true;
    }
    public String nextLine() {
        tokenizer = new StringTokenizer("");
        return innerNextLine();
    }
    public String next() {
        hasNext();
        return tokenizer.nextToken();
    }
    public int nextInt() {
        return Integer.valueOf(next());
    }
    public long nextLong() {
        return Long.valueOf(next());
    }
    public double nextDouble() {
        return Double.valueOf(next());
    }
    public BigDecimal nextBigDecimal(){ return new BigDecimal(next()); }
    public BigInteger nextBigInteger() {
        return new BigInteger(next());
    }
    @Override
    public void close() throws IOException {
        reader.close();
    }
}

// Fast writer for ACM By Azure99
class AWriter implements Closeable {
    private BufferedWriter writer;

    public AWriter(OutputStream outputStream) {
        writer = new BufferedWriter(new OutputStreamWriter(outputStream));
    }

    public void print(Object object) throws IOException {
        writer.write(object.toString());
    }

    public void println(Object object) throws IOException {
        writer.write(object.toString());
        writer.write("\n");
    }

    @Override
    public void close() throws IOException {
        writer.close();
    }
}
