#include <bits/stdc++.h>
using namespace std;
const int mod =1000000007; 
int main(){
  int n;cin>>n;
  if(n==1){
    cout<<1<<endl;
    return 0;  
  }

  vector<int> kk(n+5),kp(n+5),pk(n+5);
  kk[2]=1,kp[2]=1,pk[2]=0;
  
  for(int i=2;i<n;++i){
    kk[i+1]=pk[i]%mod;
    kp[i+1]=(kk[i]%mod+pk[i]%mod)%mod;
    pk[i+1]=kp[i]%mod;
  }
  
  int ans=(kk[n]%mod+kp[n]%mod+pk[n]%mod)%mod;
  cout<<ans<<endl;
}