testcases:
  - name: "testcase 1"
    inputs:
    - 1 : ["FreqStack", "push()", "push()", "push()", "push()", "pop()"]
    - 2 : [null, 5, 7, 7, 5, null]
    output: 
    - 1 : [null, null, null, null, null, 5]
  
  - name: "testcase 2"
    inputs:
    - 1: ["FreqStack", "push()", "push()", "push()", "push()", "pop()"]
    - 2: [null, 5, 7, 7, 14, null]
    output:
    - 1 : [null, null, null, null, null, 7]

  - name: "testcase 3"
    inputs:
    - 1: ["FreqStack", "push()", "pop()"]
    - 2: [null, 4, null]
    output:
    - 1 : [null, null, 4]

  - name: "testcase 4"
    inputs:
    - 1: ["FreqStack", "push()", "push()", "push()", "pop()", "push()", "push()", "push()", "pop()", "pop()"]
    - 2: [null, 5, 4, 9, null, 3, 7, 5, null, null]
    output:
    - 1 : [null, null, null, null, 9, null, null, null, 5, 7]

  - name: "testcase 5"
    inputs:
    - 1 : ["FreqStack", "push()", "pop()", "push()", "push()", "pop()"]
    - 2 : [null, 5, null, 4, 1, null]
    output: 
    - 1 : [null, null, 5, null, null, 1]