#include <iostream>
using namespace std;
int main(){
int n, x;
cin >> n;
for(int i = 0 ; i < n ; ++ i)
cin >> x[i];
bool ok = true;
for(int i = 0 ; i < n – 1 ; i++ )
if(x[i] * x[i + 1] == 1)
ok = false;
if(ok)
cout << “DA”;
else
cout << “NU”;
return 0;
}