#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <cmath>using namespace std;const int N=100;int n;struct Big{    int d[N],l;    int& operator [](int x){return d[x];}    Big(){l=1;memset(d,0,sizeof(d));}}f[105];Big operator *(Big a,int b){    int g=0;    for(int i=1;i<=a.l;i++){        g+=a[i]*b;        a[i]=g%10;        g/=10;    }    for(;g;g/=10) a[++a.l]=g%10;    return a;}    Big operator -(Big a,Big b){    for(int i=1;i<=b.l;i++){        if(a[i]<b[i]) a[i]+=10,a[i+1]--;        a[i]-=b[i];    }    int p=b.l+1;    while(a[p]<0) a[p]+=10,a[p+1]--;    while(a[a.l]==0) a.l--;    return a;}Big operator +(Big a,int b){    int g=b,i=1;    for(;g;i++) g+=a[i],a[i]=g%10,g/=10;    a.l=max(a.l,i);    return a;}void print(Big &a){    for(int i=a.l;i>=1;i--) printf("%d",a[i]);}    int main(){    scanf("%d",&n);    f[1].l=1;f[1][1]=1;    f[2].l=1;f[2][1]=5;    for(int i=3;i<=n;i++) f[i]=f[i-1]*3-f[i-2]+2;    print(f[n]);}