[R] how to read this kind of csv in R？

[vod vos]

I got hundreds of csv files. The real formats in each csv file are as follows:

aa(cm)
1, 2 , 3,

bb(mm)
1, 2, 3,
4, 5, 6,
7, 8, 9,

cc(mm)
3, 4, 5,
7, 5, 9,
6, 5, 8,

How can I use read.table or read.csv to convert the csv files 
to a tidy data frame format as follow:

aa, bb, cc
1, 1, 3
1, 2, 4
1, 3, 5
2, 4, 7
2, 5, 5
2, 6, 9
3, 7, 6
3, 8, 5
3, 9, 8

many thanks.