#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int arr[n + 1];
  for (int i = 0; i < n; i++) {
    cin >> arr[i];
  }
  if (n % 2 == 1 && arr[0] % 2 == 1 && arr[n - 1] % 2 == 1) {
    cout << "yes" << endl;
  } else {
    cout << "no" << endl;
  }
}
