How to give multiple objects in json input using jmeter for testing

I'm trying to give multiple Json object input to jmeter for performance testing. My input body is something like this:

{
 "ABC": {
        },
 "XYZ": [
    {
      "PId": 13,
      "CIds": [
       1234
              ]
    },
    {
      "PId": 14,
      "CIds": [
       1234
              ]     
    }
        ]
}

What would be best way to give such multiple inputs 1 million times where my PId can range from 1 to 1 million or more?

I have tried simple copy paste input values till 100 or 1000 but I'm trying to figure out a better way to give input for such 1 million records.