You are given a math word problem and you are supposed to apply an addition mathematical operator on the numbers embedded in the text to answer the following question and then only report the final numerical answer.
Q: Context: For the walls of the house he would use 12 large planks of wood and 10 small planks. If large planks together need 15 pieces of nails to be secured and small planks together need 5 nails.

Question: How many nails does John need for the house wall?
A:
20