Off topic:How can I count the alphabat of column 2 against similar number of column one in R

Question

[tcf.hcdg]

I have the data in two columns C1 and C2.

C1  C2
1   a      
1   a
1   x  
1   z 
2   a
2   y 
3   x
3   x
3   x
3   z
..

I want the output in the form how many time alphabet occurs against a specific number of C1.

For example select all the number "1" from column one and then search how many time alphabet occurs against the selected number. and then go for the next umber of column 1 do the same thing and so on till last.

1   a(2)      
    x(1)
    z(1)  
2   a(1)      
    y(1) 
3   x(3)      
    z(1)
..

Please suggest me how can I get the desired output.

Thanks in advance