update formula generator

scripts/formula_generator.py

@@ -207,13 +207,15 @@ def generate_formulas(model_name,
         if (is_satisfied is None):
             continue
 
-        # if number of explored states is not satisfied
-        if not check_explored_states(model_name, model_instance, f, timeout,
-                                     min_explored_states, paths):
-            continue
-
         # add to formulas satisfied
         if is_satisfied and len(true_formulas) < n:
+            # if number of explored states is not satisfied
+            has_explored_states = check_explored_states(
+                model_name, model_instance, f, timeout, min_explored_states,
+                paths)
+            if not has_explored_states:
+                continue
+
             true_formulas.append(f)
             write_formula(model_name, model_instance, f, formula_id, paths)
             formula_id = formula_id + 1