How to add two specific columns from a colSums table in r?

Question

I made a frequency table with two variables in a data frame using this:

    table(df$Variable1, df$Variable2)

The output was this:

             1    2    3    4    5    D    R
        1 5000   21   39    2   10    0  112
        2 1028   11   18    4    8    1   54
        3 1501    6   12    2    3    0   68
        4  355    2    4    0    0    0   23
        5  421    4    4    0    0    0   49

Then I wanted to find the sum of the first two columns so I did this:

    colSums(table(df$Variable1, df$Variable2))

The output was this:

       1    2    3    4    5    D    R 
     8305   44   77   8   21    1  306 

Is there a way to find the sum of columns 1 and 2 from the colSums output above? What would the code be? Thanks in advance.