# Max Factor

Time Limit: 1000MS

Memory Limit: 65536K

## Description

To improve the organization of his farm, Farmer John labels each of his N (1 <= N <= 5,000) cows with a distinct serial number in the range 1..20,000. Unfortunately, he is unaware that the cows interpret some serial numbers as better than others. In particular, a cow whose serial number has the highest prime factor enjoys the highest social standing among all the other cows.
(Recall that a prime number is just a number that has no divisors except for 1 and itself. The number 7 is prime while the number 6, being divisible by 2 and 3, is not).
Given a set of N (1 <= N <= 5,000) serial numbers in the range 1..20,000, determine the one that has the largest prime factor.

## Output

* Line 1: The integer with the largest prime factor. If there are more than one, output the one that appears earliest in the input file.

## Hint

OUTPUT DETAILS:

19 is a prime factor of 38. No other input number has a larger prime factor.

## Source

USACO 2005 October Bronze