Removing quote marks from blockquote css

My parent theme puts quotes around the words inside a blockquote. The CSS it uses to do this is:

	/* U.S. English quotes. */

	.en-us blockquote p { quotes: '\201C' '\201D'; }

		.en-us blockquote p::before,
		.en-us blockquote p:first-child::before { content: '\201C';  }

		.en-us blockquote p:last-child::after,
		.en-us blockquote p.is-last-child::after { content: '\201D'; }

		.en-us blockquote p.has-cite:last-child::after,
		.en-us blockquote p.has-cite:last-child::before,
		.en-us blockquote p.has-cite-only:last-child::after,
		.en-us blockquote p.has-cite-only:last-child::before { content: ''; }

What do I need to put in my child theme CSS to remove these quote marks completely? (I don’t want to change any other aspect of the theme’s blockquote CSS.)

Thanks in advance!