#include<bits/stdc++.h>
#define MOD 1000000007
#define rep(i,n)for(int i=0;i<n;i++)
using namespace std;
typedef long long ll;

ll dp[1000001][3];//何回目でその時けんは何回続いてるか
int main() {
	int n; scanf("%d", &n);
	dp[0][0] = 1;
	for (int i = 1; i <= n; i++) {
		dp[i][0] = (dp[i - 1][1] + dp[i - 1][2]) % MOD;
		for (int j = 1; j <= 2; j++)dp[i][j] = dp[i - 1][j - 1];
	}
	printf("%lld\n", (dp[n][0] + dp[n][1] + dp[n][2]) % MOD);
}