#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;

int N;

long dp[1000000][4];

long jump(int now, int back_jump){
    if(now >= N){
        return now == N;
    }else if(dp[now][back_jump] != -1){
        return dp[now][back_jump];
    }else{
        long ans = 0;
        for(int i = 1; i <= 3; i++){
            if(i != back_jump){
                ans += jump(now + i, i);
            }
        }
        return dp[now][back_jump] = ans % long(1e9 + 7);
    }
}

int main(){
    cin >> N;
    dp[0][0] = -1;
    for(int i = 0; i < 1000000; i++){
        dp[i][1] = -1;
        dp[i][2] = -1;
        dp[i][3] = -1;
    }
    cout << jump(0, 0) << endl;
}