#include <bits/stdc++.h>
const int INF = 0x3f3f3f3f;
const int maxn = 2e5 + 50;
const double eps = 1e-4;
const double PI = acos(-1);
const double UL = 1 - sqrt(3) / 2;
const double UU = sqrt(3) / 2 - 0.5;
using namespace std;
int s[maxn];
int n;
bool odd(int x) { return x & 1; }
bool check() { return odd(n) && odd(s[0]) && odd(s[n - 1]); }
int main() {
  while (~scanf("%d", &n)) {
    for (int i = 0; i < n; i++) scanf("%d", &s[i]);
    if (check()) {
      puts("yes");
    } else
      puts("no");
  }
  return 0;
}
