//https://ncode.syosetu.com/n4830bu/314/
#include <bits/stdc++.h>
using namespace std;

#include "atcoder/all"
using namespace atcoder;
using Mint = modint1000000007;

int main() {
    int N;
    cin >> N;
    vector<Mint> maine(N + 3);
    maine[0] = 1;
    for (int i = 0; i < N + 2; i++) {
        for (int j = 2; j <= 3; j++) {
            if (i - j >= 0)
                maine[i] += maine[i - j];
        }
    }
    cout << (maine[N + 1] + maine[N]).val() << endl;
}