#include <iostream>
using namespace std;
int main ()
{
int n, i, nr0, v, nr, este=1, neste=1;
cout<<"n=";
cin>> n;
cout<<"nr0=";
cin>>nr0;
cout<<"v=";
cin>>v;
for (i=1; i<n; i++)
{
cout<<"nr=";
cin>>nr;
if(i<=v)
{
if(nr<=nr-1)
este=0;
}
else
{
if(nr<=nr+1)
neste=0;
}
}
if(este==1 && neste==1)
cout<<"Da";
else
cout<<"Nu";
return 0;
}