diff --git a/SL.jl b/SL.jl
index 36c381a..fe29cfc 100644
--- a/SL.jl
+++ b/SL.jl
@@ -119,7 +119,7 @@ ID(n::Int) = eye(Int, n)
 
 function ID(n::Int, p::Int)
     p==0 && return ID(n)
-    return [Mod(x,p) for x in eye(Int,N)]
+    return [Mod(x,p) for x in eye(Int,n)]
 end