#include <bits/stdc++.h>
#define MOD 1000000007
typedef long long ll;
using namespace std;

ll N;
vector<ll> dp1(1000001, 0);
vector<ll> dp2(1000001, 0);
vector<ll> dp3(1000001, 0);

int main(void){
    
    cin >> N;
    
    dp1[1] = dp2[2] = dp3[3] = 1;
    for(int i = 1; i <= N; ++i){
        dp1[i] += dp2[i - 1] + dp3[i - 1];
        if(i - 2 >= 0) dp2[i] += dp1[i - 2] + dp3[i - 2];
        if(i - 3 >= 0) dp3[i] += dp1[i - 3] + dp2[i - 3];
        dp1[i] %= MOD, dp2[i] %= MOD, dp3[i] %= MOD;
    }
    
    cout << (dp1[N] + dp2[N] + dp3[N]) % MOD << endl;
    
    return 0;
}