[{
  "exerciseType": "GRAMMAR",
  "totalTrueCases": 5,
  "totalFalseCases": 2,
  "containLetters": ["a", "b"],
  "randomStringLength": [0, 15],
  "description": "Write a grammar for the alphabet $\\Sigma = \\{a, b\\}$ and language $L = \\{a^nb^{2n} \\mid n > 0\\}$.",
  "testCases":
  [{
    "abb": true,
    "ShowTestCase":true
  },
   {
     "aabbbb": true,
     "ShowTestCase":true
   },
   {
     "aaaaabbbbbbbbbb": true,
     "ShowTestCase":true
   },
   {
     "aaaabbbbbbbb": true,
     "ShowTestCase":true
   },
   {
     "aaabbbbbb": true,
     "ShowTestCase":true
   },
   {
     "bb": false,
     "ShowTestCase":true
   },
   {
     "aaaa": false,
     "ShowTestCase":true
   }
  ],
  "solution":
  [{
    "S": "aSbb"
  },
   {
     "S": "abb"
   }
  ]
}]