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.

Restricciones

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

Ejemplos

Entrada:
n = 84

Salida esperada:
expected = 7

Entrada:
long long n = 84;

Salida esperada:
long long expected = 7;

Entrada:
long n = 84;

Salida esperada:
long expected = 7;

Entrada:
n = 13

Salida esperada:
expected = 13

Entrada:
long long n = 13;

Salida esperada:
long long expected = 13;

Entrada:
long n = 13;

Salida esperada:
long expected = 13;

Referencias

Este reto está adaptado para CodeUtility. Sigue el enunciado y las restricciones indicadas arriba.

• #3 Largest Prime Factor