diff --git a/setup.py b/setup.py
index 21473ec..cd7cfbc 100644
--- a/setup.py
+++ b/setup.py
@@ -22,7 +22,7 @@
       author_email='tamer@fbk.eu',
       url='https://tamer.fbk.eu',
       packages=['up_tamer'],
-      install_requires=['pytamer==0.1.19', 'ConfigSpace'],
+      install_requires=['pytamer==0.1.20', 'ConfigSpace'],
       python_requires='>=3.7',
       license='APACHE'
 )
diff --git a/up_tamer/__init__.py b/up_tamer/__init__.py
index 1e9dcda..31b4190 100644
--- a/up_tamer/__init__.py
+++ b/up_tamer/__init__.py
@@ -16,7 +16,7 @@
 import re
 
 
-VERSION = (1, 1, 3)
+VERSION = (1, 1, 4)
 __version__ = ".".join(str(x) for x in VERSION)
 
 try:
diff --git a/up_tamer/converter.py b/up_tamer/converter.py
index 055a4ff..0f3d8fb 100644
--- a/up_tamer/converter.py
+++ b/up_tamer/converter.py
@@ -15,7 +15,7 @@
 
 import unified_planning as up
 from unified_planning.model import FNode
-from unified_planning.model.walkers import DagWalker
+from unified_planning.model.walkers import DagWalker, Dnf
 import pytamer # type: ignore
 from fractions import Fraction
 from typing import Dict, List
@@ -30,6 +30,7 @@ def __init__(self, env: pytamer.tamer_env,
                  parameters: Dict['up.model.Parameter', pytamer.tamer_param]={}):
         DagWalker.__init__(self)
         self._env = env
+        self._to_dnf = Dnf(problem.environment)
         self._fluents = fluents
         self._constants = constants
         self._instances = instances
@@ -42,7 +43,7 @@ def __init__(self, env: pytamer.tamer_env,
 
     def convert(self, expression: 'FNode') -> pytamer.tamer_expr:
         """Converts the given expression."""
-        return self.walk(expression)
+        return self.walk(self._to_dnf.get_dnf_expression(expression))
 
     def convert_back(self, expression: pytamer.tamer_expr) -> 'FNode':
         if pytamer.tamer_expr_is_boolean_constant(self._env, expression) == 1: