import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        long[][][] dp = new long[n + 1][3][2];
        dp[0][0][0] = 1;
        for (int i = 1; i <= n; i++) {
            for (int j = 0; j < 10; j++) {
                if (j == 3) {
                    for (int k = 0; k < 3; k++) {
                        dp[i][(k + j) % 3][1] += dp[i - 1][k][0] + dp[i - 1][k][1];
                    }
                } else {
                    for (int k = 0; k < 3; k++) {
                        dp[i][(k + j) % 3][0] += dp[i - 1][k][0];
                        dp[i][(k + j) % 3][1] += dp[i - 1][k][1];
                    }
                }
            }
        }
        long ans = dp[n][0][0];
        for (int i = 0; i < 3; i++) {
            ans += dp[n][i][1];
        }
        ans--;
        System.out.println(ans);
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String nextLine() throws Exception {
        return br.readLine();
    }
    
    public String next() throws Exception {
        if (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}