diff --git a/contrib/images/digitalocean/files/var/lib/cloud/scripts/per-once/001_setup b/contrib/images/digitalocean/files/var/lib/cloud/scripts/per-once/001_setup
index 9da800a0f..b343d77dc 100755
--- a/contrib/images/digitalocean/files/var/lib/cloud/scripts/per-once/001_setup
+++ b/contrib/images/digitalocean/files/var/lib/cloud/scripts/per-once/001_setup
@@ -19,7 +19,7 @@ for count in {1..30}; do
     ran=0
     exit 0
   else
-    count=$(($count + 1))
+    count=$((count + 1))
   fi
   sleep 5
 done