How to plot a confusion matrix using heatmaps in R?

Question

I have a confusion matrix such that:

  a b c d e f g h i j
a 5 4 0 0 0 0 0 0 0 0
b 0 0 0 0 0 0 0 0 0 0
c 0 0 4 0 0 0 0 0 0 0
d 0 0 0 0 0 0 0 0 0 0
e 2 0 0 0 2 0 0 0 0 0
f 1 0 0 0 0 2 0 0 0 0
g 0 0 0 0 0 0 0 0 0 0
h 0 0 0 0 0 0 0 0 0 0 
i 0 0 0 0 0 0 0 0 0 0 
j 0 0 0 0 0 0 0 0 0 0 

where the letters denote the class labels.

I just need to plot the confusion matrix. I searched a couple of tools. Heatmaps in R looks like what I need. As I don't know anything about R, it is really hard to do changes on the samples. If anybody could help me shortly how to draw, I will be really appreciated. Or any other suggestion rather than heatmaps are welcome as well. I know there is plenty of samples about this, but still I cannot manage to draw with my own data.