#include <iostream>
#include <vector>

using namespace std;
typedef long long ll;
const ll MOD = 1e9 + 7;

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