#include using namespace std;
int main(){ int n, x1005; 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; }