diff --git a/Part3/09_memory/kernel/kernel.c b/Part3/09_memory/kernel/kernel.c
index bf94b35..b2b2daa 100644
--- a/Part3/09_memory/kernel/kernel.c
+++ b/Part3/09_memory/kernel/kernel.c
@@ -39,7 +39,7 @@
             if (sstrlen(input, 15) > 4) {
                 char *number = input + 4;
                 u32 result = digit_conver(number);
-                if (result < 10000) {
+                if (result < 10000 || result == -1) {
                     kprint("That memory address is reserved by the Kernel, addresses must be 10000+");
                 } else {
                     umem_head = add_node( umem_head, result, 0x100, true, global_id++);