mount

#include <iostream>
using namespace std;

int main ()
{

unsigned long long n,uc,ok=0;

cin>>n;
uc=n%10;
n/=10;
 while (n)
{
    if (n%10>uc)
    {
        uc=n%10;
        n/=10;
    }
    else {
    //uc=n%10;
    ok=1;
    break;
    }
}
//cout<<uc<<n%10;
if (uc==n%10)
{
    cout<<"NU";
    return 0;
}
cout<<endl;
n/=10;
while (n)
{
     if (n%10<uc)
     {
         uc=n%10;
         n/=10;
     }
    else
    break;
}

 if (!n&&ok)
 cout<<"da";
 else
    cout<<"nu";

    return 0;
}