class BankingSystemLevel3(BankingSystem):
    def __init__(self):
        super().__init__()
        # Additional data structures for handling transfers and their state
        self.transfers = {}
        self.next_transfer_id = 1
        self.transfer_expiry_time = 86400000  # 24 hours in milliseconds

    def transfer(self, timestamp, source_account_id, target_account_id, amount):
        # Initiate a transfer between accounts
        if source_account_id not in self.accounts or target_account_id not in self.accounts:
            return ""
        if self.accounts[source_account_id] < amount:
            return ""
        if source_account_id == target_account_id:
            return ""

        # Create a transfer record
        transfer_id = f"transfer{self.next_transfer_id}"
        self.next_transfer_id += 1
        self.transfers[transfer_id] = {
            'source_account_id': source_account_id,
            'target_account_id': target_account_id,
            'amount': amount,
            'timestamp': int(timestamp),
            'status': 'pending'
        }

        # Deduct the amount from the source account balance
        self.accounts[source_account_id] -= amount
        return transfer_id

    def accept_transfer(self, timestamp, account_id, transfer_id):
        # Accept a pending transfer if it is valid and has not expired
        timestamp = int(timestamp)
        if transfer_id not in self.transfers:
            return "false"

        transfer = self.transfers[transfer_id]
        if transfer['status'] != 'pending':
            return "false"
        if transfer['target_account_id'] != account_id:
            return "false"
        if timestamp - transfer['timestamp'] > self.transfer_expiry_time:
            # Transfer has expired, refund the source account
            self.accounts[transfer['source_account_id']] += transfer['amount']
            transfer['status'] = 'expired'
            return "false"

        # Transfer is accepted
        self.accounts[account_id] += transfer['amount']
        transfer['status'] = 'accepted'
        # Update transaction totals for both accounts
        self.transaction_totals[source_account_id] = self.transaction_totals.get(source_account_id, 0) + amount
        self.transaction_totals[target_account_id] = self.transaction_totals.get(target_account_id, 0) + amount
        return "true"

    def process_queries(self, queries):
        results = []
        for query in queries:
            operation, *params = query
            if operation == "TRANSFER":
                results.append(self.transfer(*params))
            elif operation == "ACCEPT_TRANSFER":
                results.append(self.accept_transfer(*params))
            else:
                # For other operations, use the base class methods
                result = super().process_queries([query])[0]
                results.append(result)
        return results

# Create an instance of the banking system with level 3 functionality
banking_system_level3 = BankingSystemLevel3()

# Example queries for level 3
queries_level_3 = [
    ["CREATE_ACCOUNT", "1", "account1"],
    ["CREATE_ACCOUNT", "2", "account2"],
    ["DEPOSIT", "3", "account1", "2000"],
    ["DEPOSIT", "4", "account2", "3000"],
    ["TRANSFER", "5", "account1", "account2", "500"],
    # ... (other queries as per the level 3 specification)
]

# Process the level 3 queries
output_level_3 = banking_system_level3.process_queries(queries_level_3)
output_level_3