diff --git a/src/grammars/mblf.pest b/src/grammars/mblf.pest
index 54f5e6c..d5882b2 100644
--- a/src/grammars/mblf.pest
+++ b/src/grammars/mblf.pest
@@ -1,7 +1,7 @@
 operator       = @{ "operator" } // TODO
 operand        = @{ "operand" }  // TODO
 
-instruction    = { operator ~ (" "+ ~ operand)* }
+instruction    = { operator ~ (" "+ ~ operand)? }
 
 loopBlockStart = { "[" }
 loopBlockEnd   = { "]" }