import 'dart:io';



main() {
  var array =[[5,6,6,4,3],[8,9,7]];
  for(var i =0; i<array.length;i++){
  print("Case #${i+1}: ${separateArray(array[i])}");
  }
  }





separateArray(array){

  List<int> odds = new List((array.length / 2).floor());
  List<int> evens= new List(array.length - odds.length);

  int m, n;
  m = 0;
  n = 0;
  for(var i = 0; i<array.length; i++){
    if(i%2==0){
     evens[n] = array[i];
     n++;
    }
    if(i%2!=0){
      odds[m] = array[i];
      m++;
    }
  }
  evens = evens..sort();
  odds = odds..sort();
  var j=0,k=0;
  for(var i=0; i<array.length-1;i++){
    if(i%2==0){
      if (evens[j] > odds[k]) {
          return i;
      }
      j++;
    }else{
      if (odds[k] > evens[j]) {
        return i;
      }
      k++;
    }
  }
  return "OK";
}