#include <bits/stdc++.h>
using namespace std;
#define FOR(i, n) for(int i = 0; i < (n); i++)
#define MEM(a, x) memset(a, x, sizeof(a))
#define ALL(a) a.begin(), a.end()
#define UNIQUE(a) a.erase(unique(ALL(a)), a.end())
typedef long long ll;

ll dp[1000005][4], MOD = 1000000007;
int n;

int main(int argc, char const *argv[]) {
	ios_base::sync_with_stdio(false);
	cin >> n;
	dp[1][1] = 1;
	dp[2][2] = 1;
	dp[3][1] = 1;
	dp[3][2] = 1;
	dp[3][3] = 1;
	for (int i = 4; i <= n; i++) {
		dp[i][1] = (dp[i-1][2] + dp[i-1][3]) % MOD;
		dp[i][2] = (dp[i-2][1] + dp[i-2][3]) % MOD;
		dp[i][3] = (dp[i-3][1] + dp[i-3][2]) % MOD;
	}
	cout << ((dp[n][1] + dp[n][2]) % MOD + dp[n][3]) % MOD << endl;
	return 0;
}