testcases:
  - name: "testcase 1"
    inputs:
    - 1 : [['B', 'A'],['C', 'A'], ['D', 'C'], ['E', 'D'], ['E', 'B']]
    output:
    - 1 : []
  - name: "testcase 2"
    inputs:
    - 1: [['B', 'A'], ['C', 'A'], ['D', 'B'], ['E', 'B'], ['E', 'D'], ['E', 'C'], ['F', 'D'], ['F', 'E'], ['F', 'C']]
    output:
    - 1 : []
  - name: "testcase 3"
    inputs:
    - 1: [['A', 'B'], ['B', 'A']]
    output:
    - 1 : []
  - name: "testcase 4"
    inputs:
    - 1: [['B', 'C'], ['C', 'A'], ['A', 'F']]
    output:
    - 1 : []
  - name: "testcase 5"
    inputs:
    - 1: [['C', 'C']]
    output:
    - 1 : []