#include <iostream>
using namespace std;

int main() {
    int n;
    cin >> n;
    long long dp[3][n];
    dp[0][0] = 1;
    dp[1][0] = dp[2][0] = 0;
    for (int i = 1; i < n; i++) {
        dp[0][i] = dp[2][i-1];
        dp[1][i] = dp[0][i-1];
        dp[2][i] = (dp[0][i-1] + dp[1][i-1]) % 1000000007;
    }
    cout << (dp[0][n-1] + dp[1][n-1] + dp[2][n-1]) % 1000000007 << endl;
    return 0;
}