def euler(faces, edges, verticies):
    """
    Calculate the value of Euler's formula of a shape.

    :type faces: integer
    :param faces: The faces of the shape

    :type edges: integer
    :param edges: The edges of the shape

    :type verticies: integer
    :param verticies: The verticies of the shape

    :return: The result of the euler operation
    :rtype: number
    """

    # Return the calculated value
    return verticies + edges - faces