diff --git a/pps_ws/src/d_fall_pps/launch/Agent.launch b/pps_ws/src/d_fall_pps/launch/Agent.launch
index 007ce18d1f1d5325097aaabfb6f28e262583e9e8..d7712739df539bf4b13781487b9a8c961d39a09c 100755
--- a/pps_ws/src/d_fall_pps/launch/Agent.launch
+++ b/pps_ws/src/d_fall_pps/launch/Agent.launch
@@ -12,7 +12,7 @@
     <!-- Example of how to specify the agentID from command line -->
     <!-- roslaunch d_fall_pps agentID:=1 -->
 
-    <group ns="agent$(arg agentID)">
+    <group ns="$(eval 'agent' + str(agentID).zfill(3))">
 
 		<!-- CRAZY RADIO -->
 		<node