CF50E.Square Equation Roots

A schoolboy Petya studies square equations. The equations that are included in the school curriculum, usually look simple:

x_2 + 2_bx + c = 0

where b, c are natural numbers.

Petya noticed that some equations have two real roots, some of them have only one root and some equations don't have real roots at all. Moreover it turned out that several different square equations can have a common root.

Petya is interested in how many different real roots have all the equations of the type described above for all the possible pairs of numbers b and c such that 1 ≤ b ≤ n, 1 ≤ c ≤ m. Help Petya find that number.

一名中学生彼得亚正在学习一元二次方程。教材中所包含的这类方程通常形式简单：

$$x^2 + 2bx + c = 0$$

其中 $b$、$c$ 均为正整数。

彼得亚注意到，有些方程有两个实根，有些只有一个实根，而有些则没有实根。此外，他还发现若干个不同的一元二次方程可能拥有一个公共实根。

彼得亚感兴趣的是：对所有满足 $1 \leq b \leq n$、$1 \leq c \leq m$ 的正整数对 $(b, c)$，上述类型的所有方程总共能产生多少个互不相同的实根？请帮助彼得亚求出该数目。

The single line contains two integers n and m. (1 ≤ n, m ≤ 5000000).

单行包含两个整数 $n$ 和 $m$。（$1 \leq n, m \leq 5000000$）

Print a single number which is the number of real roots of the described set of equations.

输出一个整数，表示所描述方程组的实数根的个数。

In the second test from the statement the following equations are analysed:

b = 1, c = 1: x_2 + 2_x + 1 = 0; The root is x =  - 1

b = 1, c = 2: x_2 + 2_x + 2 = 0; No roots

Overall there's one root

In the second test the following equations are analysed:

b = 1, c = 1: x_2 + 2_x + 1 = 0; The root is x =  - 1

b = 1, c = 2: x_2 + 2_x + 2 = 0; No roots

b = 1, c = 3: x_2 + 2_x + 3 = 0; No roots

b = 2, c = 1: x_2 + 4_x + 1 = 0; The roots are

b = 2, c = 2: x_2 + 4_x + 2 = 0; The roots are

b = 2, c = 3: x_2 + 4_x + 3 = 0; The roots are _x_1 =  - 3, _x_2 =  - 1

b = 3, c = 1: x_2 + 6_x + 1 = 0; The roots are

b = 3, c = 2: x_2 + 6_x + 2 = 0; The roots are

b = 3, c = 3: x_2 + 6_x + 3 = 0; The roots are Overall there are 13 roots and as the root  - 1 is repeated twice, that means there are 12 different roots.

在题目描述的第二个测试用例中，分析了以下方程：

$b = 1, c = 1$: $x^2 + 2x + 1 = 0$；根为 $x = -1$

$b = 1, c = 2$: $x^2 + 2x + 2 = 0$；无实根

总计有 1 个根。

在第二个测试用例中，分析了以下方程：

$b = 1, c = 1$: $x^2 + 2x + 1 = 0$；根为 $x = -1$

$b = 1, c = 2$: $x^2 + 2x + 2 = 0$；无实根

$b = 1, c = 3$: $x^2 + 2x + 3 = 0$；无实根

$b = 2, c = 1$: $x^2 + 4x + 1 = 0$；根为

$b = 2, c = 2$: $x^2 + 4x + 2 = 0$；根为

$b = 2, c = 3$: $x^2 + 4x + 3 = 0$；根为 $x_1 = -3,\ x_2 = -1$

$b = 3, c = 1$: $x^2 + 6x + 1 = 0$；根为

$b = 3, c = 2$: $x^2 + 6x + 2 = 0$；根为

$b = 3, c = 3$: $x^2 + 6x + 3 = 0$；根为
总计有 13 个根，而根 $-1$ 重复了两次，因此共有 12 个不同的根。