#include <bits/stdc++.h>
#define REP(i,n) for (int i=0;i<(n);i++)
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define dump1d_arr(array,i) cerr << #array << "[" << (i) << "] ==> " << (array[i]) << endl;
#define dump2d_arr(array,i,j) cerr << #array << "[" << (i) << "]" << "[" << (j) << "] ==> " << (array[i][j]) << endl;
#define dump(x)  cerr << #x << " => " << (x) << endl;
#define CLR(vec) { REP(i,vec.size()) vec[i] = 0; } 
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define loINF (long)10000000000
#define shINF (short)10000
using namespace std;

typedef long long LL;
typedef vector<LL> VL;
typedef vector<VL> VVL;
const LL mod = 1e9 + 7;

int main(void){
	long N;
	cin >> N;

	VVL dp(N+1, VL(3,0));
	dp[1][1] = 1;

	FOR(i,2,N+1){
		REP(j,3){
			if (j == 0) dp[i][j] = ((dp[i-1][1] + dp[i-1][2])%mod);
			else { dp[i][j] = ((dp[i-1][j-1]) % mod);}
		}
	}

	cout << ((dp[N][0] + dp[N][1] + dp[N][2]) % mod) << endl;




	return 0;
}