[
  {
    "input": ["a"],
    "output": "a"
  },
  {
    "input": ["stress"],
    "output": "t"
  },
  {
    "input": ["moonmen"],
    "output": "e"
  },
  {
    "input": [""],
    "output": ""
  },
  {
    "input": ["abba"],
    "output": ""
  },
  {
    "input": ["aa"],
    "output": ""
  },
  {
    "input": ["~><#~><"],
    "output": "#"
  },
  {
    "input": ["hello world, eh?"],
    "output": "w"
  }
]