diff --git a/src/build/expression/Operator.go b/src/build/expression/Operator.go
index 5a48a19..a1823e1 100644
--- a/src/build/expression/Operator.go
+++ b/src/build/expression/Operator.go
@@ -14,7 +14,7 @@ type Operator struct {
 var Operators = map[string]*Operator{
 	".":   {".", 14, 2},
 	"λ":   {"λ", 13, 1},
-	"!":   {"λ", 12, 1},
+	"!":   {"!", 12, 1},
 	"*":   {"*", 11, 2},
 	"/":   {"/", 11, 2},
 	"%":   {"%", 11, 2},