#include <iostream>
#include <vector>
using namespace std;

int main() {
    int n;
    cin >> n;
    vector< vector<long long> > dp;
    dp = vector< vector<long long> >(3, vector<long long>(1000000));
    dp[0][0] = 0;
    dp[1][0] = 1;
    dp[2][0] = 0;
    long long mod= 1e9 + 7;
    for(int i=1;i<n;i++) {
        dp[0][i] = dp[2][i-1] + dp[1][i-1];
        dp[1][i] = dp[0][i-1];
        dp[2][i] = dp[1][i-1];

        for(int j=0;j<3;j++) dp[j][i] %= mod;
    }

    long long ans = 0;
    for(int i=0;i<3;i++) {
        ans += dp[i][n-1];
        ans %= mod;
    }
    cout << ans << endl;
}