Divisibility Problem

Source: Codeforces

Version: Phuoc Hung OJ Extended

Problem Statement

Given two positive integers $a$ and $b$. In one move, you may increase $a$ by exactly $1$. Find the minimum number of moves needed to make the resulting value of $a$ divisible by $b$. The answer may be $0$ if $a$ is already divisible by $b$.

Input

A single line contains two integers $a$ and $b$.

Output

Print one integer: the minimum number of moves needed.

Subtasks

• Subtask 1 (20 points): $1\le a,b\le 100$.
• Subtask 2 (30 points): $1\le a,b\le 1000000$.
• Subtask 3 (50 points): $1\le a,b\le 1000000000$.

Examples

Example 1

Input

10 4

Output

2

Explanation

For a = 10 and b = 4, the remainder a % b is 2. The minimum increment to the next multiple is 2, so the program prints 2.

Example 2

Input

92 46

Output

0

Explanation

For a = 92 and b = 46, the remainder a % b is 0. The minimum increment to the next multiple is 0, so the program prints 0.