diff --git a/src/ir/expressions/UnaryBooleanFunctionExpression.h b/src/ir/expressions/UnaryBooleanFunctionExpression.h
index 03dd1d87c..9883d6276 100644
--- a/src/ir/expressions/UnaryBooleanFunctionExpression.h
+++ b/src/ir/expressions/UnaryBooleanFunctionExpression.h
@@ -54,7 +54,7 @@ public:
 		switch (functionType) {
 		case NOT: result += "!"; break;
 		}
-		result += this->getChild()->toString();
+		result += "(" + this->getChild()->toString() + ")";
 
 		return result;
 	}
diff --git a/src/parser/PrismParser.cpp b/src/parser/PrismParser.cpp
index c7b0b9141..648962689 100644
--- a/src/parser/PrismParser.cpp
+++ b/src/parser/PrismParser.cpp
@@ -33,7 +33,6 @@ namespace parser {
  * exception is passed on to the caller.
  */
 storm::ir::Program PrismParser::parseFile(std::string const& filename) const {
-	std::cerr << "parseFile( " << filename << " )" << std::endl;
 	// Open file and initialize result.
 	std::ifstream inputFileStream(filename, std::ios::in);
 	storm::ir::Program result;