#include <cstdio>
using namespace std;
int n,s=0;

void han(int n, int a, int b, int c)
{
    if(n==1)
    {
        s++;
    }
    else
    {
        han(n-1,a,c,b);
        s++;
        han(n-1,c,b,a);
    }
}
int main()
{
    FILE *f,*g;
    f=fopen("hanoi.in","rt");
    g=fopen("hanoi.out","wt");

    fscanf(f,"%d",&n);
    han(n,1,2,3);
    fprintf(g,"%d",s);
    return 0;
}