diff --git a/randcool/randcool.hs b/randcool/randcool.hs
index cfddcafafe64c73c9b2ba45da35d65b032f0f398..d3eb3d37e8a0ab2c73ed47f738bd035046ba99f5 100644
--- a/randcool/randcool.hs
+++ b/randcool/randcool.hs
@@ -102,7 +102,7 @@ gradesBetween from to = G <$> inRange (from,to)
 
 
 numAgents :: Nat -> Rand CL
-numAgents n = CL <$> buildSet I.empty (n+1)
+numAgents n = CL <$> buildSet I.empty n
   where
     buildSet !acc m
       | m <= 0    = pure acc