#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cmath>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <sstream>
#include <string>

#define repd(i,a,b) for (int i=(a);i<(b);i++)
#define rep(i,n) repd(i,0,n)
#define var auto
#define mod 1000000007
#define inf 2147483647
#define nil -1
typedef long long ll;

using namespace std;

inline int input(){
    int a;
    cin >> a;
    return a;
}

template <typename T>
inline void output(T a, int p) {
    if(p){
        cout << fixed << setprecision(p)  << a << "\n";
    }
    else{
        cout << a << "\n";
    }
}

// end of template

int main() {
    cin.tie(0);
    // source code
    int N = input();
    vector<int> state(3, 0);
    vector<int> state_tmp(3);
    
    state[0] = 1;
    
    repd(i, 1, N){
        state_tmp[0] = state[2];
        state_tmp[1] = state[0];
        state_tmp[2] = (state[0] + state[1]) % mod;
        state = state_tmp;
    }
    
    int ret = 0;
    rep(i, 3){
        ret += state[i];
        ret %= mod;
    }
    
    output(ret, 0);
    
    return 0;
}