#include <iostream>
using namespace std;
int main() {
int n,v[50001];
bool diferite = true;
//Citire date
cin >> n;
for (int i = 1; i <= n; i++) cin >> v[i];
//Procesare
for (int i = 1; i <=n-1; i++) {
for(int j=i+1;j<=n-1;j++){
if(v[i]==v[j]) diferite = 0;
}
}
if (diferite) cout << "DA";
else cout << "NU";
}