#include <bits/stdc++.h>
using namespace std;

#define rep(i,a,b) for(int i=a;i<b;i++)
#define int long long
typedef long long ll;
const ll inf = 100100100100100;
const int mod = 1000000007;


signed main(){
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);

    int n;
    cin >> n;

    int dp1[n+1];
    int dp2[n+1];
    int dp3[n+1];
    rep(i,0,n+1){
        dp1[i] = 0; dp2[i] = 0; dp3[i] = 0;
    }

    dp1[1] = 1;
    dp2[2] = 1;
    dp1[3] = 1;
    dp2[3] = 1;
    dp3[3] = 1; 

    rep(i,4,n+1){
        dp1[i] = (dp2[i-1] + dp3[i-1]) % mod;
        dp2[i] = (dp1[i-2] + dp3[i-2]) % mod;
        dp3[i] = (dp1[i-3] + dp2[i-3]) % mod;
    }
    cout << (dp1[n] + dp2[n] + dp3[n])%mod << endl;


}