diff --git a/frontend/static/js/public.js b/frontend/static/js/public.js
index 4bef654e..121658e3 100644
--- a/frontend/static/js/public.js
+++ b/frontend/static/js/public.js
@@ -155,7 +155,10 @@ angular.module("FICApp")
 		$scope.themes = themes;
 		$scope.max_gain = 0;
 		angular.forEach(themes, function(theme, key) {
-		    this[key].exercice_count = Object.keys(theme.exercices).length;
+		    if (theme.exercices)
+			this[key].exercice_count = Object.keys(theme.exercices).length;
+		    else
+			this[key].exercice_count = 0;
 		    this[key].gain = 0;
 		    angular.forEach(theme.exercices, function(ex, k) {
 			this.gain += ex.gain;
diff --git a/frontend/static/public.html b/frontend/static/public.html
index 24c38884..8e165af2 100644
--- a/frontend/static/public.html
+++ b/frontend/static/public.html
@@ -120,7 +120,7 @@
 	      </thead>
 	      <tbody class="table-bordered bg-secondary text-dark" ng-if="s.params.kind == 'levels'">
 		<tr ng-repeat="lvl in s.params.levels">
-		  <th class="text-center"><nobr>Niveau {{ lvl }}</nobr></th>
+		  <th class="text-center"><nobr>Challenge {{ lvl }}</nobr></th>
 		  <td ng-repeat="(tid,th) in themes" class="text-center" ng-if="s.params.themes.indexOf(tid-0) !== -1">
 		    <span ng-repeat="exercice in th.exercices" ng-if="$index == lvl-1 && (exercice.tried || lvl == 1)" ng-class="{'text-primary': exercice.solved == 0, 'text-success': exercice.solved >= 1, 'text-bold': exercice.solved >= 1, 'text-warning': exercice.solved == 0 && exercice.tried}">
 		      <span ng-if="exercice.solved">{{ exercice.solved }}</span>