/* http://projecteuler.net/
 *
 * Problem 3
 * What is the largest prime factor of the number 317584931803?
 *
 * Solution by Melkor (Filip Niksic, fniksic@gmail.com)
 *
 **/

#include <iostream>

using namespace std;

int main() {
    long long n = 317584931803LL, factor = 1;

    while (n > 1) {
	factor += 2;
	while (n % factor == 0)
	    n /= factor;
    }

    cout << factor << endl;

    return 0;
}