need help in c#

Question

i have 1 2 : 3 , now i have to remove the ":" , after that need split it .
i had already success to remove the ":".
now my problem is 1 2 3, i just wan to split the 3 only.
after split the 3, 1 2 still maintain.
i wan the output is shown below :
1 2 3
1 2
3

May i know to to split the 3 only?