#include <bits/stdc++.h>
using namespace std;
using ll = long long;

ll a[1000005];
ll b[1000005];
ll c[1000005];

ll const mod = 1e9+7;

int main(){
  int n; cin >> n;
  a[2] = 1; b[2] = 1; c[2] = 0;
  int ans = 0;
  if(n==1) ans = 1;
  if(n==2) ans = 2;
  if(n>=3){
    for(int i = 3; i <= n; i++){
      a[i] = (b[i-1]+c[i-1])%mod;
      b[i] = c[i-1]%mod;
      c[i] = a[i-1]%mod;
    }
    ans = (a[n] + b[n] + c[n])%mod;
    ans = (ans+mod)%mod;
  }
  cout << ans << endl;
  return 0;
}