diff --git a/Dockerfile b/Dockerfile
index 49a0b6e..c9b5be8 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -69,6 +69,7 @@ RUN apt-get update \
     locales \
     m4 \
     make \
+    ncal \
     neovim \
     net-tools \
     openjdk-17-jdk \