#include <iostream>

using namespace std;
using LL = long long;
using ULL = unsigned long long;

constexpr int MOD = 1'000'000'007;
LL dp[1'000'001][3];

int main() {
    int N;
    cin >> N;

    dp[0][0] = 1;
    for (int i = 1; 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];
    }

    cout << (dp[N][0] + dp[N][1] + dp[N][2]) % MOD << endl;
}