// ＵＴＦ−８

#include<bits/stdc++.h>
/* #include<atcoder/all> */
/* using namespace atcoder; */

using namespace std;
using ll = long long int;
using lc = complex<ll>;

template<class T>bool chmax(T &a, const T &b) { return (a<b ? (a=b,1) : 0); }
template<class T>bool chmin(T &a, const T &b) { return (a>b ? (a=b,1) : 0); }

int main(void) {
    constexpr ll MOD = 1 ? 1e9+7 : 998244353;
    constexpr double PI = acos(-1);
    constexpr double eps = 1e-10;
    cout << fixed << setprecision(32);
    cin.tie(0); ios::sync_with_stdio(false);

    if(1) {
        ll n;
        cin >> n;
        vector<vector<ll>> dp(n+5, vector<ll>(4));

        dp[1][1] = dp[2][2] = dp[3][3] = 1;
        for(ll i=0; i<=n; i++) {
            if(i-1>=0) dp[i][1] += (dp[i-1][2] + dp[i-1][3]) % MOD;
            if(i-2>=0) dp[i][2] += (dp[i-2][1] + dp[i-2][3]) % MOD;
            if(i-3>=0) dp[i][3] += (dp[i-3][2] + dp[i-3][1]) % MOD;
        }
        cout << (dp[n][1] + dp[n][2] + dp[n][3]) % MOD << endl;
    }

    return 0;
}