#include <fstream>

using namespace std;
ifstream cin("alice_xi.in");
ofstream cout("alice_xi.out");
int n,a[36][36];
unsigned long long s=0;
int main()
{
    cin>>n;
    /*a[1][1]=1;
    a[2][1]=1;
    a[2][2]=1;*/
    for(int i=1;i<=n;i++)
        for(int j=1;j<=i;j++)
        if((i==1&&j==1)||(i==2&&j==2)||(i==2&&j==1))a[i][j]=1;
        else a[i][j]+=a[i-1][j]+a[i-1][j+1]+a[i-1][j-1];


            //else a[i][j]+=a[i-1][j]

            for(int j=1;j<=n;j++)
                s+=a[n][j];
            cout<<s;
    /*for(int i=1;i<=n;i++)
    {
        cout<<endl;

        for(int j=1;j<=i;j++)
    {
        cout<<a[i][j]<<" ";
    }
    }*/
    return 0;
}