#include <fstream>

using namespace std;

int main()

{
    ifstream in("bitona.in");
    ofstream out("bitona.out");
    int n,i,x,y,cresc=0,descr=0,a,c=0,d=0;
    in>>n;
    in>>a;
    x=a;
    for (i=2;i<=n;i++)

    {
        in>>y;
        if (x>=y)
        {
            if (cresc==0) c++;
            cresc=1;
            descr=0;
        }
        if (x<=y)
        {
            if (descr==0)d++;
            cresc=0;
            descr=1;
        }
      x=y;
    }
    if (a<x)c--;
    if (a>x) d--;
    if (c==1 && d<2) out<<"DA";
    else out<<"NU";
    return 0;

}