If we take the minimum number for a fighter squadron to be 18 - that's 180 new fighter jets in the space of 13 years. That is very, very ambitious.
Considering our current number is around 40-45!
We follow 1squadron=16 fighters.
160 fighters in 13 years shouldn't be a big deal since it won't be procured from a single source. We just need to secure the deals early for mass supply.