diff --git a/assets/js/smithwaterman.js b/assets/js/smithwaterman.js
index 26f30b3..65fe708 100644
--- a/assets/js/smithwaterman.js
+++ b/assets/js/smithwaterman.js
@@ -484,7 +484,7 @@ function checkTracebacks(){
     var j = path[x][1];
     highlightCell(`tableD`, i, j, color)
   }
-  if (correct) {
+  if (correct & l1.value.length > 0 & l2.value.length > 0) {
       var [as1, as2] = buildAlignmentCorrect(scoring["seqA"], scoring["seqB"], path)
       if (as1 === l1.value & as2 === l2.value) {
         l1.style.backgroundColor = "var(--right-answer)"
diff --git a/exercise-sheet-5.Rmd b/exercise-sheet-5.Rmd
index f3f5d39..ca682e6 100644
--- a/exercise-sheet-5.Rmd
+++ b/exercise-sheet-5.Rmd
@@ -331,7 +331,7 @@ Programming assignments are available via Github Classroom and contain automatic
 
 We recommend doing these assignments since they will help you to further understand this topic.
 
-Access the Github Classroom link: [Programming Assignment: Sheet 05](https://classroom.github.com/a/5VhpNzsi).
+Access the Github Classroom link: [Programming Assignment: Sheet 05](https://classroom.github.com/a/wqeEko6h).
 
 -------------------------------------------