Below is an instruction that describes a task. Write a response that appropriately completes the request in English. Please answer in English.

### Instruction:
Johnny buys 15 packs of colored pencils for his class. Each pack has a red, yellow, and green pencil inside. When he gets home he notices that 3 of the packs have two extra red pencils inside. How many red colored pencils did Johnny buy?

### Response:
Johnny should have 15 * 1 = <<15*1=15>>15 red pencils.
3 of the packs have 2 extra red pencils, so there are 3 * 2 = <<3*2=6>>6 extra red pencils.
Johnny has a total of 15 + 6 = <<15+6=21>>21 red pencils.
#### 21