#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define REP(i, n) for(int i = 0; i < n; i++)
const ll MOD = 1e9 + 7;

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

    ll a = 0, b = 1, c = 0;
    REP(i, n - 1) {
        ll aa = a, bb = b, cc = c;
        a = (bb + cc) % MOD;
        b = aa % MOD;
        c = bb % MOD;
    }

    ll ans = (a + b + c) % MOD;
    cout << ans << endl;
    return 0;
}