#include <iostream>
using namespace std;
int main() {
unsigned n, cif;
cin>>n;
cif = n%10;
while(n) {
n /= 10;
if(n%10>=cif) { // Pt strict crescator. Daca vrei doar crescator, elimina egalul
cout<<"NU";
return 0;
}
cif = n%10;
}
cout<<"DA";
return 0;
}