diff --git a/ACU/Trace.pm b/ACU/Trace.pm
index 6981eea..9e08935 100644
--- a/ACU/Trace.pm
+++ b/ACU/Trace.pm
@@ -146,6 +146,23 @@ sub getIds
     return \%ids;
 }
 
+sub getNonZeroIds
+{
+    my $self = shift;
+    my $login = shift;
+
+    my %ids;
+    foreach my $group (@{ $self->{groups} })
+    {
+	my %tmp = $group->getIds($login);
+	while (my ($key, $value) = each %tmp)
+	{
+	    $ids{$key} = $value if $value;
+	}
+    }
+    return \%ids;
+}
+
 sub getValue
 {
     my $self = shift;
diff --git a/process/files/intradata_get.pl b/process/files/intradata_get.pl
index 3efbce9..294fbcd 100644
--- a/process/files/intradata_get.pl
+++ b/process/files/intradata_get.pl
@@ -145,7 +145,7 @@ sub grades_generate
 	    log DEBUG, "Fill from file: $path";
 	    log TRACE, $trace->getIds($login);
 
-	    $grading->fill($trace->getIds($login));
+	    $grading->fill($trace->getNonZeroIds($login));
 	}
 
 	log DEBUG, "Computed grades: ".$grading->compute($login);