[R] Help with a cumullative Hazrd Ratio plot

[Bernardo Rangel Tura]

Hi R-masters

I need help to make modified cumulative hazard ratio plot.

I need create a common plot but with the number of subjects in risk each
ticks times for two different groups in bottom of plot (I put one
example in attach).

Do you know a routine for this?
Is possible create a routine for this? 
In this case with how commands?

Thanks in advance!
-- 
Bernardo Rangel Tura, M.D,MPH,Ph.D
National Institute of Cardiology
Brazil