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.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.time.temporal.JulianFields;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeSet;

import javax.swing.JLabel;

public class answertillD {
	static int minn;

	static class pair implements Comparable<pair> {
		int u;
		int v;

		public pair(int uo, int vo) {
			u = uo;
			v = vo;

		}

		@Override
		public String toString() {
			return "pair [u=" + u + ", v=" + v + "]";
		}

		@Override
		public int compareTo(pair e) {
			if (u == e.u && v == e.v)
				return 0;
			if (u > e.u || e.u > u)
				return u - e.u;
			else
				return 1;
		}
	}

	static class edge implements Comparable<edge> {
		int u;
		int v;
		int w;

		@Override
		public String toString() {
			return "edge [u=" + u + ", v=" + v + ", w=" + w + "]";
		}

		public edge(int uo, int vo, int wo) {
			u = uo;
			v = vo;
			w = wo;
		}

		@Override
		public int compareTo(edge e) {
			// TODO Auto-generated method stub
			return w - e.w;
		}
	}

	public static long power(long x, long y) {
		long ans = 1;
		while (y-- > 0) {
			if (ans <= 1e18 / x)
				ans *= x;
			else {
				ans = Long.MAX_VALUE;
				break;
			}
		}
		return ans;
	}

	public static char[][] reb() {
		int n = smallArr.length;
		char[][] arr = new char[n][n];
		for (int i = 0; i < n; i++)
			for (int j = 0; j < n; j++)
				arr[i][j] = smallArr[n - j - 1][i];

		return arr;
	}

	static char[] Arr, cost, level;
	static char[][] smallArr;
	static int[][][] memo;
	static int n;
	static long S;
	static final int VISITED = 2, EXPLORED = 1, UNVISITED = 0;
	static ArrayList<Integer>[] adjList;
	static boolean[] visited, adjMat[];
	static int V, E;

	static long bfs(String str, int k) {
		Queue<String> q = new LinkedList<String>();
		q.add(str);
		HashSet<String> hs = new HashSet<String>();
		hs.add(str);
		HashMap<String, Integer> hm = new HashMap<String, Integer>();
		hm.put(str, 0);
		long ans = 0;
		while (k > 0 && !q.isEmpty()) {
			String u = q.remove();
			for (int v = 0; v < u.length(); v++) {
				String sam = u.substring(0, v) + u.substring(v + 1);
				if (!hm.containsKey(sam)) {
					int x = hm.get(u) + 1;
					hm.put(sam, x);
					k--;
					ans += x;
					if (k == 0)
						break;
					q.add(sam);
				}
			}

		}
		if (k != 0)
			return -1;
		return ans;

	}

	public static long GCD(long a, long b) {
		if (b == 0)
			return a;
		return GCD(b, a % b);
	}

	public static long powerlog(long x, long y) {
		long res = 1; // Initialize result
		while (y > 0) {
			if ((y & 1) == 1)
				res = (res * x);
			// res %= 998244353;
			y = y >> 1; // y = y/2
			x = (x * x);
			// x %= 998244353;
		}
		return res;
	}

	public static String rev(String str) {
		StringBuilder sb = new StringBuilder();
		for (int i = str.length() - 1; i >= 0; i--) {
			sb.append(str.charAt(i));
		}
		return sb + "";
	}

	public static boolean checj(int numa, int b, int a, int n, int k) {
		int numb = n - numa;
		if (k % a == 0) {
			if (k / a - 1 < numa)
				return false;
		} else {
			if (k / a < numa)
				return false;
		}
		k -= numa * a;
		if (k % b == 0) {
			if (k / b - 1 < numb)
				return false;
		} else {
			if (k / b < numb)
				return false;
		}
		return true;
	}

	public static int dp(int previdx, int idx, int rem) {
		if (rem == 0)
			return 0;
		if (idx == n)
			return (int) -(1e9);
		if (memo[previdx][idx][rem] != -1)
			return memo[previdx][idx][rem];
		int remove = 0;
		int leave = dp(idx, idx + 1, rem);
		if (leave < 0)
			leave = 0;
		if (previdx == n || Arr[previdx] != Arr[idx])
			remove = 1 + dp(previdx, idx + 1, rem - 1);
		if (remove < 0)
			remove = 0;
		return memo[previdx][idx][rem] = leave + remove;
	}

	public static void main(String[] args) throws IOException, InterruptedException {
		Scanner sc = new Scanner(System.in);
		PrintWriter pw = new PrintWriter(System.out);
		long h = sc.nextInt();
		long l = sc.nextInt();
		double ans=l*l-h*h;
		System.out.println(ans/(2*h*1d));
	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}

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

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

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

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

		public double nextDouble() throws IOException {
			String x = next();
			StringBuilder sb = new StringBuilder("0");
			double res = 0, f = 1;
			boolean dec = false, neg = false;
			int start = 0;
			if (x.charAt(0) == '-') {
				neg = true;
				start++;
			}
			for (int i = start; i < x.length(); i++)
				if (x.charAt(i) == '.') {
					res = Long.parseLong(sb.toString());
					sb = new StringBuilder("0");
					dec = true;
				} else {
					sb.append(x.charAt(i));
					if (dec)
						f *= 10;
				}
			res += Long.parseLong(sb.toString()) / f;
			return res * (neg ? -1 : 1);
		}

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

	}

}
