#include <set>
#include <map>
#include <list>
#include <queue>
#include <stack>
#include <cmath>
#include <ctime>
#include <cstdio>
#include <vector>
#include <string>
#include <bitset>
#include <cctype>
#include <cstdlib>
#include <cstring>
#include <utility>
#include <numeric>
#include <complex>
#include <sstream>
#include <fstream>
#include <functional>
#include <iomanip>
#include <cassert>
#include <iostream>
#include <iterator>
#include <algorithm>
using namespace std;
typedef long long ll;
const double EPS = 1e-9;
typedef vector<int> vec;
typedef pair<int, int> P;
#define rep(n) REP(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define in(a) cin >> a;
#define out(a) cout << a << endl;
#define REP(i, x, n) for(int i = x; i < n; i++)
#define INF 100000000
#define MOD 1000000007
int dy[] = { 1,0,-1,0 }, dx[] = { 0,1,0,-1 };

long long dp[1000005][4] = { 0 };

int main() {
	int n;
	cin >> n;
	for (int i = 1; i <= n; i++) {
		dp[i][1] = dp[i - 1][2] + dp[i - 1][3];
		if(i>=2) dp[i][2] = dp[i - 2][1] + dp[i - 2][3];
		if(i>=3) dp[i][3] = dp[i - 3][1] + dp[i - 3][2];
		dp[1][1] = 1;
		dp[2][2] = 1;
		dp[3][3] = 1;
		dp[i][1] %= MOD;
		dp[i][2] %= MOD;
		dp[i][3] %= MOD;
	}
	cout << (dp[n][1] + dp[n][2] + dp[n][3])%MOD << endl;
	return 0;
}