#include <bits/stdc++.h>
using namespace std;
#define repl(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define rep(i,n) repl(i,0,n)
#define mp(a,b) make_pair((a),(b))
#define pb(a) push_back((a))
#define all(x) (x).begin(),(x).end()
#define uniq(x) sort(all(x)),(x).erase(unique(all(x)),end(x))
#define fi first
#define se second
#define dbg(...) _dbg(#__VA_ARGS__",", __VA_ARGS__)
void _dbg(string){cout<<endl;}
template<class H,class... T> void _dbg(string s,H h,T... t){int l=s.find(',');cout<<s.substr(0,l)<<" = "<<h<<", ";_dbg(s.substr(l+1),t...);}
template<class T,class U> ostream& operator<<(ostream& o, const pair<T,U> &p){o<<"("<<p.fi<<","<<p.se<<")";return o;}
template<class T> ostream& operator<<(ostream& o, const vector<T> &v){o<<"[";for(T t:v){o<<t<<",";}o<<"]";return o;}

#define INF 1120000000
#define MOD 1000000007

long dp[1000001][3];

int main(){
  int n;
  cin>>n;
  fill(dp[0], dp[n+1], 0);
  dp[0][1] = 1;
  rep(i,n-1){
    dp[i+1][0] = (dp[i][1]+dp[i][2])%MOD;
    dp[i+1][1] = dp[i][0];
    dp[i+1][2] = dp[i][1];
  }

  cout << (dp[n-1][0]+dp[n-1][1]+dp[n-1][2])%MOD << endl;

  return 0;
}