Help calculating Combinations

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A boy has n objects to paint, ordered in a row and numbered form left to right starting from 1. There are totally c colors, numbered from 0 to c-1. At the beginning all objects are colored in color with number 1. When object with color a is painted in color b, the resulting color will have color (a*b) mod c.

Now he is going to make k turns. At i-th turn he will randomly choose any subset (even empty) of objects with indices in range [Li; Ri] (inclusive) and paint all objects in chosen subset with random color (the same for all objects in the subset).

Now for given values of N,C,K. and K pairs of integers Li and Ri ,

we have to calculate the expected sum of all colors over all n objects after making all k turns. Help !!.

Example :

4 3 4

1 2

2 4

3 3

1 4

Ans : 3.44444444

I've been trying this from some time with no result.

I want a way on how to do this , please help!!.