Help to fill the last month of each quarter

[nhnn1986]

Hi all, I want to have VBA macro auto fill value year and month each quarter:
When I type in sheet(main).rane(A2) and run macro => sheet(data_result).range(C2) = sheet(main).rane(A2), range(D2).value = next quarter and continuously with range(G2), range(J2),range(M2)

It look like:
If sheet(main).range(A2) = 202012 or 202011 or 202010 then in sheet(data_result) (C2 = sheet(main).range(A2) .value, D2 = 202009, G2 = 202006, J2 = 202003 and M2 = 201912
Or If sheet(main).range(A2) = 202009 or 202008 or 202007 then in sheet(data_result) (C2 = sheet(main).range(A2) .value, D2 = 202006, G2 = 202003, J2 = 201912 and M2 = 201909
And so on

Monthly_quater.xlsx
	A	B	C	D	E	F	G	H	I	J	K	L	M	N	O
1	Header	Header	Perid1	Perid 2	Compare		Perid 3	Compare		Perid 4	Compare		Perid 5	Compare
2			202012	202009	=C-D	=E/D	202006	=C-G	=H/G	202003	=C-J	=K/J	201912	=C-M	=N/M
Data_result