How to calculate the maximum height

Question

I am studying radio galaxies and observing the behavior of fluxes at high frequencies and want to calculate the maximum height of the fluxes at where they best correspond(typically at higher frequencies).

My first graph shows

N(<S) vs log(S)

but I want to show instead.

N(>S) vs log(S) 

Any idea on how I can do this? I merely switched the axis using a computer code, but I was told I need to compute the max height instead. Graphs here Thanks in advanced!

Answer 1

It looks from the graphs that $N(<S) + N(>S) = 100$, can you not compute one from the other?