Or 'shard' it into 40 sheets of 45 rows each. Deputize 40 administrators, give them each the 45 phone numbers for their districts. At the appointed time, have

Or 'shard' it into 40 sheets of 45 rows each. Deputize 40 administrators, give them each the 45 phone numbers for their districts. At the appointed time, have the administrators direct-dial each of the 45 numbers and quickly note the results. Combine the results from the 40 as they come in. Secure and effective. It'd probably take 3 hours to wrap it all up.