C

#define _CRT_SECURE_NO_DEPRECATE

#include <iostream>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>

#define ull unsigned long long

using namespace std;

ull d[21][10];

int main() {
	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
	int n;
	cin >> n;
	d[1][0] = 0;
	for (int i = 1; i < 10; i++) {
		d[1][i] = 1;
	}
	for (int i = 2; i <= n; i++) {
		d[i][0] = d[i - 1][0] + d[i - 1][1];
		d[i][9] = d[i - 1][9] + d[i - 1][8];
		for (int j = 1; j < 9; j++) {
			d[i][j] = d[i - 1][j - 1] + d[i - 1][j] + d[i - 1][j + 1];
		}
	}
	ull ans = 0;
	for (int i = 0; i < 10; i++) {
		ans += d[n][i];
	}
	cout << ans;
	return 0;
}