#include <iostream>
#include <stdio.h>
#include <cstring>
#include <math.h>
#include <algorithm>
#include <vector>
#include <string>
#include <stdlib.h>
#include <queue>
#include <utility>
#define rep(i,n) for(int i=0;i<n;i++)
#define rrep(i,n) for(int i=n-1;i>=0;i--)
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define ll long long
#define LL long long
#define INF 100000000
#define mod 1000000007
using namespace std;
int keta(int n,int k){return (n/int(pow(10,double(k-1)))) % 10;} //nの下からk桁目
ll gcd(ll n,ll m){
	if(n<m){ll a=m;m=n;n=a;}
	ll r=n%m;
	while(r!=0){
		n=m;
		m=r;
		r=n%m;
	}
	return m;
}
ll lcm(ll n,ll m){
	return n*m/gcd(n,m);
}

int main(){
	int n;
	cin>>n;
	if(n==1){
		cout<<1<<endl;
		return 0;
	}
	vector<ll> a,b,c;
	a.resize(n);
	b.resize(n);
	c.resize(n);
	a[0]=0;b[0]=1;c[0]=0;
	FOR(i,1,n){
		a[i]=(b[i-1]+c[i-1])%mod;
		b[i]=a[i-1]%mod;
		c[i]=b[i-1]%mod;
	}
	cout<<(a[n-1]+b[n-1]+c[n-1])%mod<<endl;

}