import re


def reduce_product_name(product_name):
    """
    Remove volatile parts of the product name, to obtain a symmetry between L1C and L2A products.
    """
    m = re.match(r'(S2(?:A|B)_MSIL(?:1C|2A)_(?:[\dT]+))_N\d+_(R\d+_[0-9A-Z]+)_(?:[\dT]+)', product_name)
    if m:
        return "{}_{}".format(m.group(1), m.group(2))