A good first step is to add a little indentation and white space so you can more easliy see the control structures and flow of the program. A little like using sentence and paragraph structure in prose. Consider this:

Start

G = 18
H = 2
I = 13

if H = 2
   perform Change-GI
endif

while I > 7
   perform Change-HI
endwhile

if G = 2 then
   perform Change-G
endif

if I = G then
   perform Change-G
else
   perform Change-HI
endif

print G, H, I
End


Change-GI
   while I > 5
      I = I - 3
      G = 0
   endwhile
   Return

Change-HI
   H = H + 2
   I = I - 4
   Return

Change-G
   G = G + 1
   H = H - 1
   Return
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