#AT1436. D - Disjoint Set of Common Divisors
D - Disjoint Set of Common Divisors
D - Disjoint Set of Common Divisors
Score : $400$ points
Problem Statement
Given are positive integers $A$ and $B$.
Let us choose some number of positive common divisors of $A$ and $B$.
Here, any two of the chosen divisors must be coprime.
At most, how many divisors can we choose?
Definition of common divisor
An integer $d$ is said to be a common divisor of integers $x$ and $y$ when $d$ divides both $x$ and $y$.
Definition of being coprime
Integers $x$ and $y$ are said to be coprime when $x$ and $y$ have no positive common divisors other than $1$.
Definition of dividing
An integer $x$ is said to divide another integer $y$ when there exists an integer $\alpha$ such that $y = \alpha x$.
Constraints
- All values in input are integers.
- $1 \leq A, B \leq 10^{12}$
Input
Input is given from Standard Input in the following format:
Output
Print the maximum number of divisors that can be chosen to satisfy the condition.
12 18
3
$12$ and $18$ have the following positive common divisors: $1$, $2$, $3$, and $6$.
$1$ and $2$ are coprime, $2$ and $3$ are coprime, and $3$ and $1$ are coprime, so we can choose $1$, $2$, and $3$, which achieve the maximum result.
420 660
4
1 2019
1
$1$ and $2019$ have no positive common divisors other than $1$.