#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
using ll = long long ;
using P = pair<int,int> ;
using pll = pair<long long,long long>;
constexpr int INF = 1e9;
constexpr long long LINF = 1e17;
constexpr int MOD = 1000000007;


int main(){
    int n;
    cin >> n;
    vector<vector<ll>> dp(n,vector<ll>(3,0));
    rep(i,min(n,3)){
        dp[i][i] = 1;
    }
    rep(i,n){
        rep(j,3){
            if(i-j-1>=0){
                dp[i][j] = (dp[i-j-1][(j+1)%3] + dp[i-j-1][(j+2)%3])%MOD;
            }
        }
    }
    cout << (dp[n-1][0] + dp[n-1][1] + dp[n-1][2])%MOD << endl;
    return 0;
}