#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n);i++)
#define sz(x) int(x.size())
typedef long long ll;
typedef pair<int,int> P;

const int mod = 1e9+7;

int dp[2][2];

int main(){
  int n;
  cin >> n;
  dp[0][0] = 1;
  dp[1][0] = 1;
  rep(i,n-2){
    int tmp = dp[1][0];
    dp[1][0] = (dp[0][0] + dp[0][1]) % mod;
    dp[0][0] = dp[0][1];
    dp[0][1] = tmp;
  }
  cout << (dp[0][0] + dp[0][1] + dp[1][0]) % mod << endl;
  return 0;
}