diff --git a/instances/ipc-1998-gripper/prob01.pddl b/instances/ipc-1998-gripper/problem-01.pddl
similarity index 100%
rename from instances/ipc-1998-gripper/prob01.pddl
rename to instances/ipc-1998-gripper/problem-01.pddl
diff --git a/instances/ipc-1998-gripper/prob02.pddl b/instances/ipc-1998-gripper/problem-02.pddl
similarity index 100%
rename from instances/ipc-1998-gripper/prob02.pddl
rename to instances/ipc-1998-gripper/problem-02.pddl
diff --git a/instances/ipc-1998-gripper/solutions b/instances/ipc-1998-gripper/solutions
index 9a4318f..4354c1d 100644
--- a/instances/ipc-1998-gripper/solutions
+++ b/instances/ipc-1998-gripper/solutions
@@ -1,4 +1,4 @@
 instance | minimal horizon | #solutions with minimal horizon
 ============================================================
-prob01.pddl | 11 | 384
-prob02.pddl | 17 | 46080
+problem-01.pddl | 11 | 384
+problem-02.pddl | 17 | 46080