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.

<image>

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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class Main1 {
	static PrintWriter out = new PrintWriter(System.out);
	static FastReader input = new FastReader();

	public static void main(String[] args) throws IOException {

		double h = input.nextDouble();
		double l = input.nextDouble();

		double x = (l*l-h*h)/(2*h);
		out.println(x);
		
		out.flush();
	}

	static class con {
		static int IINF = (int) 1e9;
		static int _IINF = (int) -1e9;
		static long LINF = (long) 1e15;
		static long _LINF = (long) -1e15;
		static double EPS = 1e-9;
	}

	static class Triple implements Comparable<Triple> {
		int x;
		int y;
		int z;

		Triple(int x, int y, int z) {
			this.x = x;
			this.y = y;
			this.z = z;
		}

		@Override
		public int compareTo(Triple o) {
			if (x == o.x && y == o.y)
				return z - o.z;
			if (x == o.x)
				return y - o.y;
			return x - o.x;
		}

		@Override
		public String toString() { return "(" + x + ", " + y + ", " + z + ")"; }
	}

	static class Pair implements Comparable<Pair> {
		int x;
		int y;

		Pair(int x, int y) {
			this.x = x;
			this.y = y;

		}

		@Override
		public int compareTo(Pair o) {
			if (x == o.x)
				return y - o.y;
			return x - o.x;
		}

		@Override
		public String toString() {

			return "(" + x + ", " + y + ")";
		}

	}

	static void shuffle(int[] a) {
		for (int i = 0; i < a.length; i++) {
			int r = i + (int) (Math.random() * (a.length - i));
			int tmp = a[r];
			a[r] = a[i];
			a[i] = tmp;
		}
	}

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

	static class DSU {

		int[] p, rank, setSize;
		int numSets;

		DSU(int n) {
			p = new int[n];
			rank = new int[n];
			setSize = new int[n];
			numSets = n;

			for (int i = 0; i < n; i++) {
				p[i] = i;
				setSize[i] = 1;
			}

		}

		int findSet(int n) { return p[n] = p[n] == n ? n : findSet(p[n]); }

		boolean isSameSet(int n, int m) { return findSet(n) == findSet(m); }

		void mergeSet(int n, int m) {

			if (!isSameSet(n, m)) {
				numSets--;
				int p1 = findSet(n);
				int p2 = findSet(m);

				if (rank[p1] > rank[p2]) {
					p[p2] = p1;
					setSize[p1] += setSize[p2];
				} else {
					p[p1] = p2;
					setSize[p2] += setSize[p1];
					if (rank[p1] == rank[p2])
						rank[p1]++;
				}
			}

		}

		int size() { return numSets; }

		int setSize(int n) { return setSize[findSet(n)]; }

	}

	static class FastReader {
		BufferedReader br;
		StringTokenizer st;

		public FastReader() { br = new BufferedReader(new InputStreamReader(System.in)); }

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

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

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

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

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

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