Task

Round the given number n to the nearest multiple of m.

If n is exactly in the middle of 2 multiples of m, return n instead.

Example

For n = 20, m = 3, the output should be 21.

For n = 19, m = 3, the output should be 18.

For n = 50, m = 100, the output should be 50.

Input/Output

• [input] integer n

1 ≤ n < 10^9.

• [input] integer m

3 ≤ m < 109.

• [output] an integer