2998

#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>

using namespace std;

typedef long long ll;

int main() {
    ifstream fin("input.txt");
    ofstream fout("output.txt");

    int n;
    const int TEN = 10;
    fin >> n;
    vector<vector<ll>> dp(n + 1, vector<ll>(TEN));
    dp[1][0] = 0;
    for (int i = 1; i < TEN; i++) dp[1][i] = 1;
    for (int i = 2; i <= n; i++) {
        dp[i][0] = dp[i - 1][0] + dp[i - 1][1];
        for (int j = 1; j < TEN - 1; j++)
            dp[i][j] = dp[i - 1][j] + dp[i - 1][j - 1] + dp[i - 1][j + 1];
        dp[i][9] = dp[i - 1][9] + dp[i - 1][8];
    }
    ll res = 0;
    for (ll i : dp[n])
        res += i;
    fout << res << endl;

    fin.close();
    fout.close();
    return 0;
}