import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        long[][] dp = new long[3][n + 1];
        dp[0][0] = 1;
        for (int i = 1; i <= n; i++) {
            for (int j = 0; j < 10; j++) {
                if (j == 3) {
                    continue;
                }
                dp[j % 3][i] += dp[0][i - 1];
                dp[(j + 1) % 3][i] += dp[1][i - 1];
                dp[(j + 2) % 3][i] += dp[2][i - 1];
            }
        }
        if (n < 19) {
            long ans = (long)(Math.pow(10, n)) - dp[1][n] - dp[2][n] - 1;
            System.out.println(ans);
        } else {
            long base = (long)(Math.pow(10, n) / 2);
            long ans = base - dp[1][n] + base - dp[2][n] - 1;
            System.out.println(ans);
        }
    }
}