--- a/progs/lecture4.scala	Fri Dec 02 07:48:03 2022 +0000
+++ b/progs/lecture4.scala	Fri Dec 02 11:05:41 2022 +0000
@@ -280,7 +280,7 @@
 // Tail recursion
 //================
 
-def fact(n: BigInt): BigInt = 
+def fact(n: Int): Int = 
   if (n == 0) 1 else n * fact(n - 1)