12 is weak, and there is no need to add chords.
There are two stresses in the 4/4 beat, which are on 1 beat and 3 beat respectively.
So my answer is two.
1 completed.
Add 135 after the first beat (that is, the first 3).
The fourth beat (that is, 2 of 2 1) becomes 572.
The last section is at the handover meeting 135.
This is the basic trend of 1-5- 1.
Two are unfinished recipes.
Still weak? number
The first beat is 135.
The third beat is converted with 725(572)
Last small savings (6 13)
Of course, there are other ways of transformation. Generally speaking, harmonic chords can be stressed, and various forms of chords (dissonance, 7 chords, 9 chords) can be converted into unstressed, and so on.
If you change the chord rhythm, you can have many different effects.
Of course, you may not need these!