CF1199B.Water Lily

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.

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 $A$?

伊内萨乘船航行时，注意到湖面上方有一朵美丽的睡莲花。她靠近后发现，这朵花恰好高出水面 $H$ 厘米。伊内萨抓住花朵，又向前航行了 $L$ 厘米，此时花朵恰好触及水面。

假设这朵睡莲生长在湖底某点 $A$ 处，且其花茎始终是一条线段，一端固定于点 $A$。再假设初始时刻花朵恰好位于点 $A$ 的正上方，即其花茎呈竖直状态。你能求出点 $A$ 处湖水的深度吗？

The only line contains two integers $H$ and $L$ ($1 \le H \lt L \le 10^{6}$).

唯一的一行包含两个整数 $H$ 和 $L$（$1 \le H \lt L \le 10^{6}$）。

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 $\frac{|A - B|}{\max{(1, |B|)}} \le 10^{-6}$.

输出一个整数——点 $A$ 处湖的深度。绝对误差或相对误差均不得超过 $10^{-6}$。

形式化地，设你的答案为 $A$，评测组的答案为 $B$。当且仅当 $\frac{|A - B|}{\max{(1, |B|)}} \le 10^{-6}$ 时，你的答案被视为正确。