Formula to return total of sub-accounts to the main account

Hello everyone. I am stuck with this problem. I basically need a formula that adds up the total of sub-accounts and posts that value against the Parent Account. I have a large data sheet so entering manually would take a lot of time. I have attached an excel sheet where i have highlighted in colors the Parent account and their sub accounts. I have manually entered the totals of sub-accounts in column C but i need a formula which would do it automatically.

To identify how a parent account relates to a sub account is a parent Account say has code 4-001-002 and a sub account has say code 4-001-002-011. The 002 is the identification that the sub account relates to the parent. It would be much easier to understand in the excel sheet i have attached.

any help would be much needed.