#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] == 0) {
    cout << "UP";
    return 0;
  }
  if (a[n - 1] == 15) {
    cout << "DOWN";
    return 0;
  }
  if (n == 1)
    cout << "-1";
  else {
    if (a[n - 1] - a[n - 2] > 0)
      cout << "UP";
    else
      cout << "DOWN";
  }
  return 0;
}
