Counting Divisors

Problem Description

Given a positive integer $n$ ($1 \le n \le 2 \times 10^9$), output the number of positive divisors of $n$, including $1$ and $n$ itself.

Input Format

One positive integer $n$.

Output Format

One integer: the number of divisors of $n$.

Sample Input

10

Sample Output

4

Constraints

$1 \le n \le 2 \times 10^9$.

Hint

• You only need to check divisors up to $\sqrt{n}$: each $i$ that divides $n$ contributes one divisor $i$ and, unless $i = n/i$, another divisor $n/i$.