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