#include<bits/stdc++.h> using namespace std; long long a[105][3]; int main(){ int n; cin>>n; if(n==1){ cout<<0; return 0; } a[1][2]=1; a[1][3]=1; for(int i=2;i<=n;i++){ a[i][1]=a[i-1][2]+a[i-1][3]; a[i][2]=a[i-1][1]+a[i-1][3]; a[i][3]=a[i-1][1]+a[i-1][2]; } cout<<a[n][1]*3; return 0; }

#include<bits/stdc++.h> using namespace std; int main(){ int n; cin >> n; long long a[50] = {}; a[1] = 0, a[2] = 6, a[3] = 6; for(int i = 4; i <= n; i++){ a[i] = a[i-1] + a[i-2] * 2; } cout << a[n]; return 0; }