I need help writing a calculator TI-84 code for 4th order Runge Kutta Method. WILL RATE!

I wrote code for Improved Euler Method, but having trouble writing Runge Kutta. Please allow code to be similar to the code I wrote. Thank you.

Improved Euler Method

:ClrHome

:Disp "X0"

:Input X

:Disp "Y0"

:Input Y

:Disp "H"

:Input H

:1->N

:Lbl A

:Y->D

:Y1->B

:Y+H*Y1->Y

:X+H->X

:Y1->C

:D+H[B+C]/2->Y

:ClrHome

:Output(1,1,"X =")

:Output(1,2,N)

:Output(1,5,X)

:Output(2,1,"Y =")

:Output(2,2,N)

:Output(2,5,Y)

:Pause

:1+N->N

:Goto A