#include <bits/stdc++.h>

using namespace std;

const long long MOD = 1e9 + 7;

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

    long long a = 0, b = 1, c = 0;
    for (int i = 0; i < n - 1; ++i) {
        long long aa = a, bb = b, cc = c;
        a = (bb + cc) % MOD;
        b = aa % MOD;
        c = bb % MOD;
    }
    
    cout << (a + b + c) % MOD << endl;
    return 0;
}