import java.util.ArrayList;
import java.util.List;

class Euler69 {

    private static class Options {
        int limit = 1000000;
        boolean runCheckpoints = true;
    }

    private static boolean parseIntAfterPrefix(String arg, String prefix, Options options) {
        if (!arg.startsWith(prefix)) {
            return false;
        }
        String tail = arg.substring(prefix.length());
        if (tail.isEmpty()) {
            return false;
        }

        int parsed = 0;
        for (int i = 0; i < tail.length(); i++) {
            char c = tail.charAt(i);
            if (c < '0' || c > '9') {
                return false;
            }
            parsed = parsed * 10 + (c - '0');
        }
        options.limit = parsed;
        return true;
    }

    private static boolean parseArguments(String[] args, Options options) {
        for (String arg : args) {
            if (arg.equals("--skip-checkpoints")) {
                options.runCheckpoints = false;
                continue;
            }
            if (parseIntAfterPrefix(arg, "--limit=", options)) {
                continue;
            }

            System.err.println("Unknown argument: " + arg);
            return false;
        }
        return options.limit >= 2;
    }

    private static List<Integer> sievePrimes(int limit) {
        boolean[] isPrime = new boolean[limit + 1];
        for (int i = 2; i <= limit; i++) {
            isPrime[i] = true;
        }
        isPrime[0] = false;
        isPrime[1] = false;

        for (int p = 2; p <= limit / p; p++) {
            if (!isPrime[p]) {
                continue;
            }
            for (int q = p * p; q <= limit; q += p) {
                isPrime[q] = false;
            }
        }

        List<Integer> primes = new ArrayList<>();
        for (int p = 2; p <= limit; p++) {
            if (isPrime[p]) {
                primes.add(p);
            }
        }
        return primes;
    }

    private static int solve(int limit) {
        List<Integer> primes = sievePrimes(100);

        long product = 1;
        for (int p : primes) {
            if (product * p > limit) {
                break;
            }
            product *= p;
        }

        return (int) product;
    }

    private static boolean runCheckpoints() {
        if (solve(10) != 6) {
            System.err.println("Checkpoint failed for limit=10");
            return false;
        }
        return true;
    }

    public static void main(String[] args) {
        Options options = new Options();
        if (!parseArguments(args, options)) {
            System.exit(1);
        }
        if (options.runCheckpoints && !runCheckpoints()) {
            System.exit(2);
        }

        System.out.println(solve(options.limit));
    }
}