#include <bits/stdc++.h>
using namespace std;
using namespace chrono;
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#endif

int main()
{
    int64_t n;
    cin >> n;

    using mint = modint1000000007;

    vector dp(n + 1, vector(3, mint(0)));

    dp[0][0] = 1;
    for (int64_t i = 0; i < n; i++)
    {
        dp[i + 1][0] += dp[i][1] + dp[i][2];
        dp[i + 1][1] += dp[i][0];
        dp[i + 1][2] += dp[i][1];
    }

    cout << (dp[n][0] + dp[n][1] + dp[n][2]).val() << endl;

    return 0;
}