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

#define int long long

typedef pair<int,int>pint;
typedef vector<int>vint;
#define pb push_back
#define mp make_pair
#define all(v) (v).begin(),(v).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define reps(i,f,n) for(int i=(f);i<(n);i++)
template<class T,class U>void chmin(T &t,U f){if(t>f)t=f;}
template<class T,class U>void chmax(T &t,U f){if(t<f)t=f;}

const int mod=1000000007;

signed main(){
    int N;cin>>N;
    int a=1,b=0,c=0;

    rep(i,N){
        int tmp=b+c;
        c=b;
        b=a;
        a=tmp%mod;
    }

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