Largest Prime Factor

A prime is an integer greater than 1 with no positive divisors other than 1 and itself. Find the largest prime factor of n. When n is itself prime, return n.

Implement largest_prime_factor(n).

Input

n: The integer to factor.

Output

Return its largest prime divisor.

Contraintes

2 ≤ n ≤ 10¹². The input 1 is excluded because it has no prime factor.

Exemples

Entrée :
n = 84

Sortie attendue :
expected = 7

Entrée :
long long n = 84;

Sortie attendue :
long long expected = 7;

Entrée :
long n = 84;

Sortie attendue :
long expected = 7;

Entrée :
n = 13

Sortie attendue :
expected = 13

Entrée :
long long n = 13;

Sortie attendue :
long long expected = 13;

Entrée :
long n = 13;

Sortie attendue :
long expected = 13;

Références

Ce défi a été adapté pour CodeUtility. Suivez l'énoncé et les contraintes ci-dessus.

• #3 Largest Prime Factor