How to sum up the price in the file that share the same consumer..For example, file one has all user's purchase history and one other file has the specific name of the user (one name only)..the language use is java language..

File1.txt

metth

File2.txt

adam, Milk, 10

metth, Chips,20

metth, Milk, 10

matth, Eggs,5

adam,Eggs, 20

andrew, ethan, Milk, 50

Now, how was the coding to get the total amount of the metth spends at all time by reading the two file input without displaying the other user's total spend?