diff --git a/ocr b/ocr
index ae1c537..1ad626f 100755
--- a/ocr
+++ b/ocr
@@ -122,11 +122,11 @@ class OCRWorkflow(WorkflowRunner):
         for job in self.jobs:
             ocropusnlbin_job_number += 1
             cmd = 'ocropus-nlbin -Q "%i" -o "%s" "%s"/*' % (
-                max(1, int(self.nCores / length(self.jobs))),
+                max(1, int(self.nCores / len(self.jobs))),
                 os.path.join(job["output_dir"], "tmp", "ocropus-nlbin"),
                 os.path.join(job["output_dir"], "tmp", "tiff_files")
             )
-            ocropusnlbin_jobs.append(self.addTask(label="ocropusnlbin_job_-_%i" % (ocropusnlbin_job_number), command=cmd, dependencies=split_jobs, nCores=max(1, int(self.nCores / length(self.jobs)))))
+            ocropusnlbin_jobs.append(self.addTask(label="ocropusnlbin_job_-_%i" % (ocropusnlbin_job_number), command=cmd, dependencies=split_jobs, nCores=max(1, int(self.nCores / len(self.jobs)))))
 
         ###
         # Task "tesseract_job": perform OCR on binarized images