diff --git a/sim.c b/sim.c
index d311b23..da2ecfa 100644
--- a/sim.c
+++ b/sim.c
@@ -648,11 +648,13 @@ static Usz hash32_shift_mult(Usz key) {
 
 BEGIN_OPERATOR(random)
   LOWERCASE_REQUIRES_BANG;
+  PORT(0, -1, IN);
   PORT(0, 1, IN);
-  PORT(0, 2, IN);
   PORT(1, 0, OUT);
-  Usz a = index_of(PEEK(0, 1));
-  Usz b = index_of(PEEK(0, 2));
+  Usz a = index_of(PEEK(0, -1));
+  Usz b = index_of(PEEK(0, 1));
+  if (b == 0)
+    b = 36;
   Usz min, max;
   if (a == b) {
     POKE(1, 0, glyph_of(a));