#include<cstring>
#define CK 10000
using namespace std;
int n;
class {
	public:
		int len;
		int s[1010];
		void clean(void){memset(s,0,sizeof(s));	len=1;}
		void write(void){printf("%d",s[len-1]);
			for (int i=len-2;i>=0;i--)	printf("%.4d",s[i]);}
};
Marvolo a,b,c;
inline Marvolo operator *(int x,Marvolo y){
	int i=0;
	for (i=0;i<=y.len-1;i++)	y.s[i]*=3;
	for (i=0;i<y.len||y.s[i]>0;i++){
		y.s[i+1]+=y.s[i]/CK;	y.s[i]%=CK;
	}
	y.len=i;
	return y;
}
inline Marvolo operator -(Marvolo x,Marvolo y){
	int i=0;
	for (i=0;i<y.len;i++)	x.s[i]-=y.s[i];
	for (i=x.len-1;i>=1;i--) x.s[i]-=1,x.s[i-1]+=CK;
	for (i=0;i<x.len||x.s[i]>0;i++){
		x.s[i+1]+=x.s[i]/CK;	x.s[i]%=CK;
	}
	x.len=i;
	return x;
}
inline Marvolo operator +(Marvolo x,int y){
	int i=0;
	x.s[0]+=2;
	for (i=0;i<x.len||x.s[i]>0;i++){
		x.s[i+1]+=x.s[i]/CK;	x.s[i]%=CK;
	}
	x.len=i;
	return x;
}
int main(){
	a.len=1;	a.s[0]=1;
	b.len=1;	b.s[0]=5;
	scanf("%d",&n);
	if (n==1) {printf("1n"); goto END;}
	else if (n==2)	{printf("5n");	goto END;}
	for (int i=3;i<=n;i++){
		c=3*b;	c=c-a; c=c+2;	a=b;	b=c;
	}
	b.write();
	END:
	return 0;
}