Bitqoins
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

Miss M lives on the planet Bitaqulandia, where the most popular currency is the bitqoin. Recently, Miss M held a mini-competition for friends, where each winner receives exactly three bitqoins.

It is known that in Miss M's competition, the prize fund is $$$n$$$ bitqoins, $$$m$$$ people won, and each winner receives exactly three bitqoins.

Determine how many bitqoins will remain with Miss M if she gives three bitqoins to each winner. It is known that Miss M has enough bitqoins.

Input

The first line contains one integer $$$n$$$ ($$$3 \leq n \leq 100$$$) — the number of bitqoins.

The second line contains one integer $$$m$$$ ($$$1 \leq m \leq 100$$$) — the number of Miss M's friends who won in the competition.

It is guaranteed that Miss M will have enough bitqoins to distribute to her winning friends.

Output

Print a single integer — the number of bitqoins that will remain with Miss M after she distributes them to the winners.

Example

Input

    10
    2

Output

    4

Note

Miss M had two friends win, she will give three bitqoins to each of them. In total, she will give away six, so only four bitqoins will remain.