#include "bits/stdc++.h"

using namespace std;

using ll = long long;
using ld = long double;
using P = pair<int, int>;
constexpr ld EPS = 1e-12;
constexpr int INF = numeric_limits<int>::max() / 2;
constexpr int MOD = 1e9 + 7;

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;
    vector<vector<ll>> dp(n + 1, vector<ll>(3, 0));
    dp[1][1] = 1;
    for (int i = 2; i <= n; i++)
    {
        dp[i][0] = (dp[i - 1][1] + dp[i - 1][2]) % MOD;
        dp[i][1] = dp[i - 1][0];
        dp[i][2] = dp[i - 1][1];
    }
    ll res = dp[n][0];
    res += dp[n][1];
    res %= MOD;
    res += dp[n][2];
    res %= MOD;
    cout << res << endl;
}