     "mimetype": "text/x-python",
     "name": "python",
     "nbconvert_exporter": "python",
     "pygments_lexer": "ipython3",
     "version": "3.4.3"
    }
   },
   "nbformat": 4,
   "nbformat_minor": 0
  }
 
</s> remove    "version": "3.4.3"
 </s> add    "version": "3.5.0" </s> remove     "%run ../stack/stack.py\n",
    "%load ../stack/stack.py"
 </s> add     "%run ../stack/stack.py" </s> remove     "            while not buff.is_empty() and buff.peek() > temp:\n",
 </s> add     "            while not buff.is_empty() and temp < buff.peek():\n",
   "version": "3.5.0"
     "mimetype": "text/x-python",
     "name": "python",
     "nbconvert_exporter": "python",
     "pygments_lexer": "ipython3",
   "version": "3.5.0"
    }
   },
   "nbformat": 4,
   "nbformat_minor": 0
  }
keep keep keep keep replace keep keep keep keep keep
 Update stack min challenge (#108)

Updates constraints and solution. 
stacks_queues/sort_stack/sort_stack_challenge.ipynb