diff --git a/cpu.mk b/cpu.mk
index fd08cf6..36cd79d 100644
--- a/cpu.mk
+++ b/cpu.mk
@@ -1,6 +1,6 @@
 CC=gcc
 CFLAGS=-O0 -I /usr/local
 $(error Please set SENDER_CPU and RECEIVER_CPU to your assigned values)
-SENDER_CPU=
-RECEIVER_CPU=
+SENDER_CPU=0
+RECEIVER_CPU=1