#include <iostream>
#include <ginac/ginac.h>
using namespace std;
using namespace GiNaC;

int main()
{
    symbol xs("x");
	lst expr;
	parser reader;
	expr=reader("{x,x}");
	cout <<"list " << expr  << endl;
	cout <<"number of elements "<< expr.nops() << endl;
	cout <<"1st el " <<expr[0] << endl;
	cout <<"2nd el, error " <<expr[1]<< endl;
    return 0;
}