diff --git a/jupyter-sage/Dockerfile b/jupyter-sage/Dockerfile
index 102bd4d..1c38776 100644
--- a/jupyter-sage/Dockerfile
+++ b/jupyter-sage/Dockerfile
@@ -1,6 +1,6 @@
 FROM debian:latest
 RUN apt-get update && apt-get upgrade
-RUN apt-get install bc binutils bzip2 ca-certificates cliquer cmake curl \
+RUN apt-get install -y bc binutils bzip2 ca-certificates cliquer cmake curl \
         ecl eclib-tools fflas-ffpack g++ gap gcc gengetopt gfan gfortran \
         glpk-utils gmp-ecm lcalc libatomic-ops-dev libboost-dev \
         libbraiding-dev libbrial-dev libbrial-groebner-dev libbz2-dev \
@@ -19,7 +19,7 @@ RUN apt-get install bc binutils bzip2 ca-certificates cliquer cmake curl \
         patchelf perl pkg-config planarity ppl-dev python3 python3-setuptools \
         python3-venv singular singular-doc sqlite3 sympow tachyon tar texinfo \
         tox xcas xz-utils git
-RUN apt-get install default-jdk dvipng ffmpeg fonts-freefont-otf \
+RUN apt-get install -y default-jdk dvipng ffmpeg fonts-freefont-otf \
         imagemagick latexmk libavdevice-dev libjpeg-dev pandoc tex-gyre \
         texlive-fonts-recommended texlive-lang-cyrillic texlive-lang-english \
         texlive-lang-european texlive-lang-french texlive-lang-german \