#include <bits/stdc++.h>
using namespace std;
#define INF 1000000000000000000
#define MOD 1000000007
using ll=long long;
using Graph=vector<vector<int>>;

int main(){
  int N;
  cin>>N;
  vector<vector<ll>> dp(N,vector<ll>(3,0));
  dp[0][1]=1;
  for(int i=1;i<N;i++){
    dp[i][0]=dp[i-1][1]+dp[i-1][2];
    dp[i][0]%=MOD;
    dp[i][1]=dp[i-1][0];
    dp[i][2]=dp[i-1][1];
  }

  ll ans=dp[N-1][0]+dp[N-1][1]+dp[N-1][2];
  ans%=MOD;
  cout<<ans<<endl;
}