diff --git a/ArithmeticCalculator.cpp b/ArithmeticCalculator.cpp
index 7df9e9f..ab16785 100644
--- a/ArithmeticCalculator.cpp
+++ b/ArithmeticCalculator.cpp
@@ -4,11 +4,11 @@
 #include "PostficCalculator.h"
 
 double ArithmeticCalculator::Solve(char* equation) {
-	SyntaxParser* parser = new SyntaxParser(equation);
+	SyntaxParser* parser = new SyntaxParser();
 	PostfixConvertor* postfixConverter = new PostfixConvertor();
 	PostfixCalculator* postfixCalculator = new PostfixCalculator();
 
-	LinkedList<FormulaItem*>* formulaList = parser->ParseExpression();
+	LinkedList<FormulaItem*>* formulaList = parser->ParseExpression(equation);
 
 	Stack<FormulaItem*>* postfixStack = postfixConverter->CreatePostfixStack(formulaList);
 
diff --git a/SyntaxParser.cpp b/SyntaxParser.cpp
index b0009f6..ba65450 100644
--- a/SyntaxParser.cpp
+++ b/SyntaxParser.cpp
@@ -4,8 +4,7 @@
 
 using namespace std;
 
-SyntaxParser::SyntaxParser(string input) {
-	_input = input;
+SyntaxParser::SyntaxParser() {
 	_parsedExpression = new LinkedList<FormulaItem*>();
 	_current = 0;
 }
@@ -122,7 +121,9 @@ void SyntaxParser::ParseNumber() {
 	delete buffer;
 }
 
-LinkedList<FormulaItem*>* SyntaxParser::ParseExpression() {
+LinkedList<FormulaItem*>* SyntaxParser::ParseExpression(string input) {
+	_input = input;
+
 	while (true) {
 		char c = GetNextChar();
 
diff --git a/SyntaxParser.h b/SyntaxParser.h
index bb0885a..ec84614 100644
--- a/SyntaxParser.h
+++ b/SyntaxParser.h
@@ -17,7 +17,7 @@ class SyntaxParser {
 	void ParseText();
 	void ParseNumber();
 public:
-	SyntaxParser(string input);
+	SyntaxParser();
 	~SyntaxParser();
-	LinkedList<FormulaItem*>* ParseExpression();
+	LinkedList<FormulaItem*>* ParseExpression(string input);
 };
\ No newline at end of file