#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
typedef long long ll;
#define rep(i,n) for (int i = 0; i < (n); ++i)

int main(){
    int N;
    cin >> N;
    vector<vector<ll>> ans(N,vector<ll>(3));
    // ans[i][0]：ケン1
    // ans[i][1]：ケン2
    // ans[i][2]：パ
    ans[0][0]=1;
    ans[0][1]=0;
    ans[0][2]=0;
    for(int i=1;i<N;i++){
        ans[i][0] = ans[i-1][2];
        ans[i][1] = ans[i-1][0];
        ans[i][2] = (ans[i-1][0] + ans[i-1][1]) % 1000000007;
    }

    ll ans_N = (ans[N-1][0] + ans[N-1][1] + ans[N-1][2]) % 1000000007;
    cout << ans_N << endl;
    return 0;
}