#include <iostream>

using namespace std;
bool f(int n)
{
    static int x = 0;

    int a;
    cin >> a;
    if(n  == 1 )cin >> x;
     else return f(n-1);
     if(x == a)return true;
     else return false;





}

int main()
{
    int n; cin >> n;
    if(f(n)) cout <<"Da";
    else cout <<"NU";
    return 0;
}