Absolute Error

Version: Phuoc Hung OJ Extended

Problem Statement

A measurement yields an approximate value $x$ and a reference value $ref$. Their absolute error is $E=|x-ref|$. Calculate $E$ and display exactly 6 digits after the decimal point.

Input

The only line contains the approximate real value $x$ and reference value $ref$.

Output

Print the absolute error $E$ with exactly 6 decimal places.

Subtasks

• Subtask 1 (100 points): $x,ref$ are finite.

Examples

Example 1

Input

99.9 100

Output

0.100000

Explanation. Substituting the input into the formula gives |99.9-(100)| ≈ 0.1. Formatting with six decimal places produces 0.100000.

Example 2

Input

1.01 1.0

Output

0.010000

Explanation. Substituting the input into the formula gives |1.01-(1.0)| ≈ 0.01. Formatting with six decimal places produces 0.010000.

Example 3

Input

-9.9 -10.0

Output

0.100000

Explanation. Substituting the input into the formula gives |-9.9-(-10.0)| ≈ 0.1. Formatting with six decimal places produces 0.100000.