diff --git a/src/utils.c b/src/utils.c
index b78ffe5..ea25f54 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -104,7 +104,7 @@
 #define AS_CHAR(digit) ((digit) + '0')
 #define INSERT_CHAR(c, b, n)                                                   \
 	{                                                                      \
-		if (n > 1) {                                                   \
+		if ((n) > 1) {                                                 \
 			*(b)++ = (c);                                          \
 			(n)--;                                                 \
 		}                                                              \