#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, e) for (int i = (int)s; i < (int)e; ++i)
#define all(a) (a).begin(), (a).end()

const ll mod = 1e9 + 7;

int main() {
    cin.tie(nullptr);
    
    int N;
    cin >> N;
    
    vector dp(N, vector<ll>(3));
    dp[0][0] = 1;
    dp[0][1] = 0;
    dp[0][2] = 0;
    
    rep(i, 1, N) {
        dp[i][0] = dp[i - 1][2];
        dp[i][1] = dp[i - 1][0];
        dp[i][2] = (dp[i - 1][0] + dp[i - 1][1]) % mod;
    }
    
    ll ans = 0;
    rep(i, 0, 3) ans += dp[N - 1][i];
    
    cout << ans % mod << '\n';
}