diff --git a/action.yml b/action.yml
index 481bb8d..b1d9f80 100644
--- a/action.yml
+++ b/action.yml
@@ -101,7 +101,7 @@ runs:
         : enable Cargo sparse registry
         # except on 1.66 and 1.67, on which it is unstable
         if [ -z ${CARGO_REGISTRIES_CRATES_IO_PROTOCOL+set} ]; then
-          if rustc +${{steps.parse.outputs.toolchain}} --version --verbose | not grep -q '^release: 1\.6[67]\.'; then
+          if rustc +${{steps.parse.outputs.toolchain}} --version --verbose | (! grep -q '^release: 1\.6[67]\.'); then
             echo CARGO_REGISTRIES_CRATES_IO_PROTOCOL=sparse >> $GITHUB_ENV
           fi
         fi