diff --git a/examples/blur.c b/examples/blur.c
index d90d355..ba03396 100644
--- a/examples/blur.c
+++ b/examples/blur.c
@@ -12,7 +12,7 @@ int main(int argc, char *argv[])
     char *srcname = NULL, *dstname = NULL;
     pipi_image_t *img, *newimg;
 
-    if(argc < 3)
+    if(argc < 4)
     {
         fprintf(stderr, "%s: too few arguments\n", argv[0]);
         fprintf(stderr, "Usage: %s <src> <radius> <dest>\n", argv[0]);