diff --git a/backup.sh b/backup.sh
index e55feaa4d08161934e66eac3e215e7045c16cf11..57a63ffcdefd7002ec376d17c032bac4993fd1f8 100755
--- a/backup.sh
+++ b/backup.sh
@@ -17,11 +17,10 @@ retrie_on_fail(){
     if [ $1 -ne 0 ]; then
         keep=$(($BK_KEEP_FULL-1))
         if [ $keep -gt 0 ]; then
-            run_duplicity remove-all-inc-of-but-n-full $(($BK_KEEP_FULL-1)) --force
+            run_duplicity remove-all-inc-of-but-n-full $keep --force
         else
             cat <<EOF | lftp $host
             user $user $ftppass
-
             rm -rf $remotedir/*-inc*
             rm -rf $remotedir/*-new-signatures*
 EOF