Average of Two Numbers

Version: Phuoc Hung OJ Extended

Problem Statement

Given two real numbers $a$ and $b$, compute their arithmetic mean $M=\dfrac{a+b}{2}$. Print it in fixed-point notation with exactly 2 decimal places.

Input

One line contains real numbers a,b.

Output

Print the arithmetic mean with exactly 2 decimal places.

Subtasks

• Subtask 1 (100 points): $|a|,|b|\le10^{12}$.

Examples

Example 1

Input

2 3

Output

2.50

Explanation. Substituting 2, 3 into (a + b) / 2 gives approximately 2.5. The required output formatting produces 2.50.

Example 2

Input

1.5 2.5

Output

2.00

Explanation. Substituting 1.5, 2.5 into (a + b) / 2 gives approximately 2. The required output formatting produces 2.00.

Example 3

Input

-3 2

Output

-0.50

Explanation. Substituting -3, 2 into (a + b) / 2 gives approximately -0.5. The required output formatting produces -0.50.