#include <bits/stdc++.h>
using namespace std;
long long n, a[200], p1, p2;
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> a[i];
  if (n % 2 == 0) {
    cout << "no";
    return 0;
  }
  if (a[1] % 2 == 1 && a[n] % 2 == 1)
    cout << "yes";
  else
    cout << "no";
  return 0;
}
