void gen(ArrayList<Integer> length, ArrayList<Integer> times) {
        if (length.size() == 0) {
            for (int i = 0; i < times.size(); i++) {
                for (int j = i + 1; j < times.size(); j++)
                    time[times.get(j) - times.get(i)] = true;
            }
            return;
        }
        for (int mask = 1; mask < pow[length.size()]; mask++) {
            int minTime = Integer.MAX_VALUE;
            for (int i = 0; i < length.size(); i++) {
                int maskI = (mask / pow[i]) % 3;
                if (maskI == 1)
                    minTime = Math.min(minTime, length.get(i));
                if (maskI == 2)
                    minTime = Math.min(minTime, length.get(i) / 2);
            }
            ArrayList<Integer> newLength = new ArrayList<Integer>();
            for (int i = 0; i < length.size(); i++) {
                int maskI = (mask / pow[i]) % 3;
                int nextLen = length.get(i);
                if (maskI == 1)
                    nextLen -= minTime;
                if (maskI == 2)
                    nextLen -= 2 * minTime;
                if (nextLen != 0)
                    newLength.add(nextLen);
            }
            times.add(times.get(times.size() - 1) + minTime);
            gen(newLength, times);
            times.remove(times.size() - 1);
        }
    }

    void precalc(int n) {
        pow = new int[n + 1];
        pow[0] = 1;
        for (int i = 1; i <= n; i++)
            pow[i] = 3 * pow[i - 1];
        ArrayList<Integer> curArr = new ArrayList<Integer>();
        for (int i = 0; i < n; i++)
            curArr.add(1 << n);
        time = new boolean[pow[n] * n + 1];
        ArrayList<Integer> times = new ArrayList<Integer>();
        times.add(0);
        time[0] = true;
        gen(curArr, times);
        ArrayList<Integer> ans = new ArrayList<Integer>();
        for (int i = 0; i <= pow[n] * n; i++)
            if (time[i])
                ans.add(i);
        for (int i = 0; i < ans.size() - 1; i++)
            out.print(ans.get(i) + ", ");
        out.print(ans.get(ans.size() - 1));
    }