Calculating Modular Arithmetic in the below way

How do I calculate:

$a \pmod c + b \pmod c$

using the modular arithmetic:

$(a+b) \pmod c = (a \pmod c + b \pmod c)\pmod c$

For example, assuming that $a=14, b=17$ and $c=5$;

$(a+b) \pmod c = (a \pmod c + b \pmod c) \pmod c$

$31 \pmod 5 = ( 4 + 2 ) \pmod 5$

I just want $6 (4+2)$ to be the output.

One way to calculate it is to perform $(a \pmod c + b \pmod c).$

But how do I calculate that value without performing in the above mentioned way but by using $(a+b) \pmod c$ ?