#!/usr/bin/env python3
from  ctypes import *
#class
class Graph(Structure):
    
class Nodo(Structure):
    id = c_int()
    def __str__():
        return self.id
class Eje(Structure):
    id=c_int()
    def __str__(self):
        return str(self.id)

a = Eje()
a.id=3
print(str(a))
