Account Transactions Given pipe-delimited files F1 and F2 where F1 contains accounts with fields ACCOUNT NUM|PIN|BALANCE and F2 contains transaction instructions COMMAND|AMOUNT|ACCOUNT NUM|PIN, execute the transactions, storing the results back in F1. The COMMAND field will be add or sub indicating addition or subtraction from the account. Transactions which do not provide the correct PIN code or attempt to put the account below zero should be ignored.