Spam Caller Counter

You are given two lists:

1. A list of phone calls, where each call is represented as a tuple (caller_id, call_time).
2. A list of spam reports, where each report is represented as a tuple (caller_id, report_time).

A caller is considered a spammer if any of their calls occurred within ±2 seconds of any spam report for the same caller_id.

Return the number of unique caller_ids that are flagged as spammers under this rule.

Note: A caller should be counted at most once regardless of how many of their calls or reports satisfy the condition.