diff --git a/include/input/PrintTools.h b/include/input/PrintTools.h
index 0ca6fa3..0e3fbb1 100644
--- a/include/input/PrintTools.h
+++ b/include/input/PrintTools.h
@@ -27,6 +27,9 @@
 
 template <size_t N>
 std::string bitsetToString(const std::bitset<N>& bitset) {
+    if (bitset.none()) {
+        return "<none>";
+    }
     return bitset.to_string();
 }