public int takeFactor(String input,int pos)
	{
		int pos1 =pos;
		if(isLetter(input,pos))	{return takeLetter(input,pos);}
		
		if(isParen(input,pos))
		{
			pos = takeParen(input,pos);
			if(isExpression(input,pos)){
				pos = takeExpression(input,pos);
				if(isCloseParen(input,pos)){return takeCloseParen(input,pos);}
			}
			
		}
		return pos1;
	}