#include<iostream>
#include<vector>
#include<algorithm>
#include<string>
#include<cmath>
#include<climits>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<bitset>
#include<iomanip>
using namespace std;

#define rep(i,j,n) for(int i=(j);i<(n);++i)
#define erep(i,j,n) for(int i=(j);i<=(n);++i)
#define all(i) i.begin(),i.end()
#define rall(i) i.rbegin(),i.rend()
#define INF 1e9
const int mod = 1e9 + 7;

typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<string> vs;
typedef vector<vector<string>> vvs;
typedef pair<int, int> pi;
typedef long long i64;

int main() {
	int n;
	cin >> n;
	vector<vector<i64>> dp(n + 1, vector<i64>(3, 0));
	dp[1][1] = 1;
	rep(i, 1, n) {
		dp[i + 1][0] = (dp[i][1] + dp[i][2]) % mod;
		dp[i + 1][1] = dp[i][0] % mod;
		dp[i + 1][2] = dp[i][1] % mod;
	}
	cout << (dp[n][0] + dp[n][1] + dp[n][2]) % mod << endl;
}