diff --git a/nemu/Makefile b/nemu/Makefile
index 25a6fa0..f5f7ef4 100644
--- a/nemu/Makefile
+++ b/nemu/Makefile
@@ -78,7 +78,7 @@ COLOR_NONE  = \033[0m
 $(IMAGES): %: %.bin $(BINARY)
 	@$(RM) .integration-test.tmp
 	@$(BINARY) -b $< > /dev/null || printf "[%14s] $(COLOR_RED)FAIL$(COLOR_NONE)\n" $(notdir $<) >> .integration-test.tmp
-	@printf "%d Failed \n" $(shell wc -l .integration-test.tmp)
+	@printf "%s Failed \n" $(shell wc -l .integration-test.tmp)
 
 integration-tests: $(IMAGES) 
 	@echo $(IMAGES_PATH)