#include<iostream>
using namespace std;
int a[103];
int main(){
    int n;
    cin>>n;
    for(int i=0;i<n;i++){
        cin>>a[i];
    }if(n==1&&a[n-1]!=15&&a[n-1]!=0){
        cout<<-1;
        return 0;
    }
    if((a[n-1]>a[n-2]&&a[n-1]!=15)||a[n-1]==0){
        cout<<"UP";
    }else{
        cout<<"DOWN";
    }
}