[R] plot the number of replicates at the same point

[Kerry Bush]

Dear R-helper,
  I want to plot the following-like data:

x y
1 1
1 1
1 2
1 3
1 3
1 4
......

In the plot that produced, I don't want to show the
usual circles or points. Instead, I want to show the
number of replicates at that point. e.g. at the
position of (1,1), there are 2 obsevations, so a
number '2' will be displayed in the plot.
Is my narrative clear? Is there a way to make the plot
in R?