How many minimum number of Chapatis did the mom made?

A farmer’s wife made some chapatis.
The farmer had 3 sons.
His fist son came, gave one chapati to the dog,
and made three equal parts of remaining chapatis,
ate one part of it and left the other two parts for his brothers.
Other two sons came one after the other and did the same
thinking that they came first.
Then at night all three came to the house,
One of them gave one chapati to dog
and made three equal parts and the three brothers ate one-one part of it.
If no chapati was broken in pieces then,
How many minimum number of Chapatis did the mom made?