Pies

Cossack Vus has exactly $n$ pies and $m$ friends.

It is known that each of his friends wants to be given exactly three pies.

Cossack Vus will not let his friends down, so he will give each of them what they want.

Determine how many pies will remain with Cossack Vus if he gives three pies to each friend. It is known that Cossack has enough pies.

Input

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

The second line contains one integer $m$ ($1\le m\le 100$) — the number of Cossack Vus's friends.

It is guaranteed that Vus will have enough pies to give to all his friends.

Output

Output one integer — the number of pies that will remain with Cossack Vus after he gives them to his friends.

Examples

Note

Cossack has two friends, to each of whom he will give three pies. In total, he will give away six, so only four pies will remain.