#include<fstream.h>
ifstream f("bac.in");

void main()
{ int n,x,mpar=0,mimp=9999,ok=1,i;
  f>>n;
  for(i=1;i<=n;i++)
  { f>>x;
	if(x%2==0) if(x>=mpar) mpar=x;
			   else ok=0;
	else if(x<=mimp) mimp=x;
		 else ok=0;
  }
  if(ok) cout<<"da";
  else cout<<"nu";

}