#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <iomanip>
#include <algorithm>
#include <vector>
#include <cmath>
#include <cstdlib>
#include <sstream>
#include <stdio.h>
#include <set>
#include <stack>
#include <map>
#include <utility>
#include <numeric>
#include <queue>
#include <complex>
using namespace std;
int arr[4] = {1,1,2,3 };

struct biginteger {
	 int cc[700];
	biginteger() {
		for (int i = 1; i < 700; ++i)
			cc[i] = 0;
		cc[0] = -1;
	}
	biginteger operator + (biginteger b)const  {
		int num = 0;
		biginteger tmp;
		tmp.cc[0]=0;
		int carry = 0;
		for (int i = 0; i < 700; ++i) {
			num = cc[i] + b.cc[i] + carry;
			if (num >= 10) {
				num -= 10;
				carry = 1;
			}
			else
				carry = 0;
			tmp.cc[i] = num;
		}
		return tmp;
	}

};
biginteger dp[1005];
void print( const biginteger n) {
	int t = 0;
	for (int i = 699; i >= 0; --i) {
		if (n.cc[i] != 0)
		{
			t = i; break;
		}
	}
	for (int i = t ; i >= 0; --i)
		printf("%d", n.cc[i]);
	printf("\n");

}

/*
stack oberflow
biginteger solve( int rem) {
	 if (rem == 0) {
		 biginteger r;
		 r.cc[0] = 1;
		 return r;
	 }
	biginteger &ret = dp[rem];
	if (ret.cc[0]!=-1)
		return ret;
	ret.cc[0] = 0;
	for (int i = 0; i < 4; ++i) {
		if(rem - arr[i]>=0)
		ret= ret + solve(rem - arr[i]);
	}
	return  ret;
}*/

int main() {
	int d;
	while (cin >> d) {
		for (int i = 0; i <= 1000; ++i) {
			for (int j = 0; j < 700; ++j)
				dp[i].cc[j] = 0;

		}
		dp[0].cc[0] = 2;
		dp[1].cc[0] = 5;
		dp[2].cc[0] = 3;
		dp[2].cc[1] = 1;
		for (int i = 3; i < d; ++i) {
			dp[i] = dp[i - 1] + dp[i - 1] + dp[i - 2] + dp[i - 3];
		}
		print(dp[d-1]);


		/*dp[0][0] = dp[1][0]= dp[2][0] = dp[3][0] = 1;

		for (int idx = 0; idx < 4; ++idx) {
			for (int coin = 1; coin <= d; coin++ ) {
				if (idx)
					dp[idx][coin] = dp[idx-1][coin];
				if (coin - arr[idx] >= 0)
					dp[idx][coin] += dp[idx][coin - arr[idx]];
			}
		}

		printf("%lld\n",  dp[3][d]);*/

	}


	return 0;

}