diff --git a/cmd/sbox/sbox.go b/cmd/sbox/sbox.go
index 03ce2d5..4f7451d 100644
--- a/cmd/sbox/sbox.go
+++ b/cmd/sbox/sbox.go
@@ -750,7 +750,7 @@
 		return false
 	}
 	defer fileA.Close()
-	fileB, err := os.Open(a)
+	fileB, err := os.Open(b)
 	if err != nil {
 		return false
 	}