import java.util.*;
 
class Main {
 
	public static boolean isOperator(char c)
	{
		switch(c)
		{
		case '+':
		case '-':
		case '/':
		case '*':
			return true;
		default:
		}
 
		return false;
	}
 
    public static boolean isStartGroup(char c)
    {
        return c == '(';
    }
 
    public static boolean isEndGroup(char c)
    {
        return c == ')';
    }
 
    public static boolean isNumber(char c)
    {
        return Character.isDigit(c);
    }
 
    public static String toInFix(String expression)
    {
        Stack<String> stack = new Stack<String>();
 
        for (int x = 0; x < expression.length(); x++)
        {
        	char c = expression.charAt(x);
 
        	if (isStartGroup(c))
        	{
        		continue;
        	}
        	else if ( isOperator(c) || isNumber(c))
        	{
        		stack.push(Character.toString(c));
        	}
            else if (isEndGroup(c))
            {
            	String arg2 = stack.pop();
            	String oper = stack.pop();
            	String arg1 = stack.pop();
 
            	stack.push(arg1 + " " + arg2 + " " + oper);
            }
        }
 
        return stack.pop();
    }
 
	public static void main(String args[]) {
		System.out.println(toInFix("(1+(2+3))"));
		System.out.println(toInFix("((1+2)+3)"));
		System.out.println(toInFix("(((1+2)+(3+4))+3)"));
	}
}