#include <bits/stdc++.h>
using namespace std;

#define INF 1.1e9
#define LINF 1.1e18
#define FOR(i,a,b) for (int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
#define pb push_back
#define pf push_front
#define fi first
#define se second
#define BIT(x,n) bitset<n>(x)
#define PI 3.14159265358979323846

typedef long long ll;
typedef pair<int,int> P;
typedef pair<ll,P> PP;

//-----------------------------------------------------------------------------

int n;
ll dp[1000010][3];
const int MOD=1e9+7;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	cin>>n;
	dp[0][0]=1;
	REP(i,n) {
		dp[i+1][0]=dp[i][1]+dp[i][2]%MOD;
		dp[i+1][1]=dp[i][0];
		dp[i+1][2]=dp[i][1];
	}
	cout<<(dp[n][0]+dp[n][1]+dp[n][2])%MOD<<endl;

	return 0;
}