class Euler38 {

    private static class Options {
        boolean runCheckpoints = true;
    }

    private static boolean parseArguments(String[] args, Options options) {
        for (int i = 0; i < args.length; ++i) {
            String arg = args[i];
            if ("--skip-checkpoints".equals(arg)) {
                options.runCheckpoints = false;
                continue;
            }
            System.err.println("Unknown argument: " + arg);
            return false;
        }
        return true;
    }

    private static boolean is1To9Pandigital(String s) {
        if (s.length() != 9) {
            return false;
        }

        boolean[] used = new boolean[10];
        for (int i = 0; i < s.length(); ++i) {
            char c = s.charAt(i);
            int d = c - '0';
            if (d <= 0 || d >= 10 || used[d]) {
                return false;
            }
            used[d] = true;
        }
        for (int d = 1; d <= 9; ++d) {
            if (!used[d]) {
                return false;
            }
        }
        return true;
    }

    private static String concatenatedProduct(int base, int maxMultiplier) {
        StringBuilder out = new StringBuilder();

        for (int n = 1; n <= maxMultiplier; ++n) {
            out.append(base * n);
        }

        return out.toString();
    }

    private static int solve() {
        int best = 0;
        for (int base = 1; base <= 9999; ++base) {
            StringBuilder concat = new StringBuilder();
            for (int n = 1; concat.length() < 9; ++n) {
                concat.append(base * n);
                if (concat.length() == 9 && n >= 2 && is1To9Pandigital(concat.toString())) {
                    int candidate = Integer.parseInt(concat.toString());
                    if (candidate > best) {
                        best = candidate;
                    }
                }
            }
        }
        return best;
    }

    private static boolean runCheckpoints() {
        if (!"192384576".equals(concatenatedProduct(192, 3))) {
            System.err.println("Checkpoint failed for base=192");
            return false;
        }
        if (!is1To9Pandigital("123456789")) {
            System.err.println("Checkpoint failed for pandigital helper");
            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());
    }
}