Split identical medicines in same dosage

Arun has to take two separate tablets – A and B for 30 days. He has stored 30 quantity of tablet A in a jar and 30 quantity of tablet B in another jar.

Both tablets are identical in appearance, weight, smell and taste. So its impossible to distinguish between A and B.

Every day he opens first jar and puts 1 tablet A in his hand. Then he opens second jar and takes 1 tablet B. He then put both of them in his mouth and swallows. This went on smoothly for 20 days.

On 21st day after taking medicine from both jars he found that he had taken 4 tablets. Help Arun to take proper dosage of medicines for 30 days.