#include  <iostream>
#include  <fstream>

using namespace std;

ifstream in("oo.in");
ofstream out("oo.out");

const int Nmax = 1e5 + 5,
          inf = 0x3f3f3f3f;
int v[Nmax],
    n;

int main()
{
  in>>n;
  for(int i = 1; i <= n; i++)
    in>>v[i];
  int ma = inf;
//  for(int i = 1; i <= 3; i++)
  //{
    int dp[Nmax] = {0};//suma maxima pana la pozitia i
    int j;
  //  if(i == 1)
      dp[1] = v[1], j = 3;
    //else if(i == 2)
  //    dp[1] = v[2] + v[3];
    //else
      //dp[1] = v[n] + v[1];
    for(; j <= n; j++)
      dp[j] = max(dp[j-1], v[j] + v[j-1] + dp[j-3]);
    //for(int i = 1; i <= n; i++)
      //cout<<dp[i]<<' ';
    //cout<<endl;
    if(ma > dp[n])
        ma = dp[n];
//  }
  out<<ma;
}