setup <- function() {
  for(door in doors(100, 100)) {
    stdout$print(paste(door, ""))
  }
}

doors <- function(ndoors=100,passes=100) {
  doors <- rep(FALSE,ndoors)
  for (ii in seq(1,passes)) {
      mask <- seq(0,ndoors,ii)
      doors[mask] <- !doors[mask]
  }
  return (which(doors == TRUE))
}