#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <math.h>
#include <cmath>
#include <limits.h>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <functional>
#include <stdio.h>
using namespace std;

long long MOD = 1000000007;

int main() {
    
    int N;
    cin >> N;
    
    long long dp[3] = {0};
    dp[0] = 1;
    
    for ( int i = 0; i < N; i++ ) {        
        long long z = 0;
        z += dp[2];
        dp[2] = dp[1];
        z += dp[1];
        dp[1] = dp[0];
        
        z %= MOD;
        
        dp[0] = z;
    }
    
    long long ans = 0;
    for ( int i = 0; i < 3; i++ ) {
        ans += dp[i];
        ans %= MOD;
    }
    
    cout << ans << endl;
    
    return 0;
}