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.util.*;
import java.lang.*;
import org.omg.PortableInterceptor.INACTIVE;
 
public class Main {
 
    private static final FS scanner = new FS(System.in);
 
	public static void main(String[] args) throws Exception {
        double h = scanner.nextDouble();
        double l = scanner.nextDouble();

        System.out.printf("%.13f", (l * l + h * h) / (2 * h) - h);
    }
	
    static class FS {
        BufferedReader br;
        StringTokenizer st;

        public FS(InputStream i) {
            br = new BufferedReader(new InputStreamReader(i));
            st = new StringTokenizer("");
        }

        public String next() throws IOException {
            if(st.hasMoreTokens())
                return st.nextToken();
            else
                st = new StringTokenizer(br.readLine());
            return next();
        }

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

        public long nextLong() throws IOException {
            return Long.parseLong(next());
        }
        public double nextDouble() throws IOException {
            return Double.parseDouble(next());
        }
    }
 
}