#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";
}
}