[
  { "operation": "transfer", "input": { "source": "A", "target": "B", "amount": 30 } },
  { "operation": "transfer", "input": { "source": "B", "target": "C", "amount": 50 } },
  { "operation": "transfer", "input": { "source": "A", "target": "C", "amount": 50 } },
  { "operation": "transfer", "input": { "source": "A", "target": "B", "amount": 200 } },
  { "operation": "transfer", "input": { "source": "A", "target": "D", "amount": 30 } },
  { "operation": "transfer", "input": { "source": "A", "target": "D", "amount": 30 } },
  { "operation": "transfer", "input": { "source": "D", "target": "A", "amount": 100 } },
  { "operation": "transfer", "input": { "source": "B", "target": "A", "amount": 10 } }
]