#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int a[n];
  for (int i = 0; i < n; i++) cin >> a[i];
  if (a[n - 1] == 15)
    cout << "DOWN" << endl;
  else if (a[n - 1] == 0)
    cout << "UP" << endl;
  else if (n == 1)
    cout << -1 << endl;
  else if (a[n - 1] > a[n - 2])
    cout << "UP" << endl;
  else
    cout << "DOWN" << endl;
}
