    }
   ],
   "metadata": {
    "kernelspec": {
     "display_name": "Python 2",
     "language": "python",
     "name": "python2"
    },
    "language_info": {
     "codemirror_mode": {
 
</s> remove    "display_name": "Python 2",
 </s> add    "display_name": "Python 3", </s> remove    "name": "python2"
 </s> add    "name": "python3" </s> remove    "name": "python2"
 </s> add    "name": "python3" </s> remove     "version": 2
 </s> add     "version": 3 </s> remove     "version": 2
 </s> add     "version": 3
   "display_name": "Python 3",
    }
   ],
   "metadata": {
    "kernelspec": {
   "display_name": "Python 3",
     "language": "python",
     "name": "python2"
    },
    "language_info": {
     "codemirror_mode": {
keep keep keep keep replace keep keep keep keep keep
 Move utopian tree challenge solution to a class (#144) 
online_judges/utopian_tree/utopian_tree_challenge.ipynb