public class Euler327 {
    static long M(int c, int rooms) {
        long f = 1;
        for (int r = 2; r <= rooms; ++r) {
            long trips = (f + c - 3) / (c - 2);
            f = f + 2 * trips - 1;
        }
        return f + 1;
    }

    public static String solve() {
        int cMin = 3;
        int cMax = 40;
        int rooms = 30;
        long sum = 0;
        for (int c = cMin; c <= cMax; ++c) {
            sum += M(c, rooms);
        }
        return String.valueOf(sum);
    }

    public static void main(String[] args) {
        System.out.println(solve());
    }
}