create::Int->Int->Int->[String]
create h w d = case mod d 2 of
              1 ->[[ odd_func d (i,j)|j<-[1..w]]|i<-[1..h]]
              0 ->[[even_func d (i,j)|j<-[1..w]]|i<-[1..h]]

odd_func::Int->(Int,Int)->Char
odd_func d (i,j) = case (mod (div i  (div (d+1) 2) ) 2,mod (div j  (div (d+1) 2) ) 2) of
                   (0,0)->'R'
                   (0,1)->'Y'
                   (1,0)->'G'
                   (1,1)->'B'

even_func::Int->(Int,Int)->Char
even_func d (i,j) = case (mod (div i (div (d+1) 2) ) 2,mod (div j ((div (d+1) 2)+1) ) 2) of
                   (0,0)->'R'
                   (0,1)->'Y'
                   (1,0)->'G'
                   (1,1)->'B'

main::IO()
main=do
  datc<-getLine
  let  h:w:d:[]=map read (words datc)
  prints (create h w d)

prints::[String]->IO()
prints []=return ()
prints (x:xs)=do
  putStr x
  putStr "\n"
  prints xs