#include <iostream>
using namespace std;

const int mod = 1e9+7;
int main(void){
    int n;
    cin >> n;
    long long sum = 0;
    long long memo[3];
    if(n == 1){
        cout << "1" << endl;
        return 0;
    }else if(n==2){
        cout << "2" << endl;
        return 0;
    }else if(n==3){
        cout << "2" << endl;
        return 0;
    }
    memo[0]=0; //けんけん
    memo[1]=1; //けんぱ
    memo[2]=1; //ぱけん
    long long tmp1, tmp2, tmp3;
    for(int i=4; i<=n; i++){
        tmp1 = memo[2];
        tmp2 = (memo[0] + memo[2])%mod;
        tmp3 = memo[1];
        memo[0] = tmp1;
        memo[1] = tmp2;
        memo[2] = tmp3;
    }
    sum = (memo[0]+memo[1]+memo[2])%mod;
    cout << sum%mod << endl;
    return 0;
}