diff --git a/logic2.tex b/logic2.tex
index da74ac4..cabf756 100644
--- a/logic2.tex
+++ b/logic2.tex
@@ -43,6 +43,7 @@
 \input{inputs/lecture_17}
 \input{inputs/lecture_18}
 \input{inputs/lecture_19}
+\input{inputs/lecture_20}
 
 
 \cleardoublepage