#include <bits/stdc++.h>
using namespace std;

#define ll long long

ll dp[100005][5][2];

int main() {
    ll n;
    cin >> n;

    dp[1][1][1] = 1;
    dp[1][2][0] = 1;
    dp[1][3][0] = 1;
    dp[1][4][0] = 1;

    for (ll i = 2; i <= n; i++) {

        dp[i][1][1] = dp[i-1][1][0] + 0 + dp[i-1][3][0] + dp[i-1][4][0];
        dp[i][1][0] = dp[i-1][1][1] + 0 + dp[i-1][3][1] + dp[i-1][4][1];

        dp[i][2][1] = 0 + dp[i-1][2][1] + 0 + dp[i-1][4][1];
        dp[i][2][0] = 0 + dp[i-1][2][0] + 0 + dp[i-1][4][0];

        dp[i][3][1] = dp[i-1][1][1] + 0 + dp[i-1][3][1] + 0;
        dp[i][3][0] = dp[i-1][1][0] + 0 + dp[i-1][3][0] + 0;

        dp[i][4][1] = dp[i-1][1][1] + dp[i-1][2][1] + 0 + dp[i-1][4][1];
        dp[i][4][0] = dp[i-1][1][0] + dp[i-1][2][0] + 0 + dp[i-1][4][0];
    }
    
    cout<<dp[n][1][1]+dp[n][2][1]+dp[n][3][1]+dp[n][4][1]<<"\n";
}