#define _USE_MATH_DEFINES
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include<queue>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include<iomanip>

//#include<bits/stdc++.h>



using namespace std;




int main() {
	

	
	int a=1,b=0,c=0,ap,bp,cp;
	int n;
	cin>>n;
	while(n--){
		ap=a,bp=b,cp=c;
		a=(bp+cp)%1000000007;
		b=ap;
		c=bp;

	}
	cout<<((a+b)%1000000007+c)%1000000007<<endl;
	return 0;
}