public class Euler191 {
    public static void main(String[] args) {
        int days = 30;
        long[][] dp = new long[2][3];
        dp[0][0] = 1;
        for (int day = 0; day < days; day++) {
            long[][] nxt = new long[2][3];
            for (int l = 0; l < 2; l++)
                for (int a = 0; a < 3; a++) {
                    long w = dp[l][a];
                    if (w == 0)
                        continue;
                    nxt[l][0] += w;
                    if (a < 2)
                        nxt[l][a + 1] += w;
                    if (l == 0)
                        nxt[1][0] += w;
                }
            dp = nxt;
        }
        long t = 0;
        for (int l = 0; l < 2; l++)
            for (int a = 0; a < 3; a++)
                t += dp[l][a];
        System.out.println(t);
    }
}