rm(list = ls())
nchooser <- function(n, r) {
 if (n == r) {
	 #cat("called nchooser(n = r)\n")
	 return(1)
 } else if (r == 0) {
	 #cat("called nchooser(r = 0)\n")
	 return(1)
 } else
   #cat("called nchooser(", n", " r ") \n")
   return((nchooser(n-1, r-1)) + nchooser(n-1, r))
}