diff --git a/program.py b/program.py
index b918dcf..a9308c2 100644
--- a/program.py
+++ b/program.py
@@ -52,7 +52,7 @@ class RegexInterpreter(AbstractInterpreter):
        
     def isValid(self,f)->bool:
         
-        formula = f.s.replace("!", "\\!")
+        formula = "({0})".format(f.s.replace("!", "\\!"))
 
         make_reg = lambda formula,pattern: 'echo "{0}" | grep -P "{1}"'.format(formula,pattern)
         def check_assertion(formula, pattern):
@@ -192,7 +192,7 @@ if len(sys.argv) > 1 :
         for l in u:
             print(Formula(l,i).isValid())
     else:
-        print(Formula( sys.argv[1],i).isValid())
+        print(Formula( sys.argv[1] if sys.argv[1] != '-g' else sys.argv[2],i).isValid())
    
 else:
     print("help?")