nostr:npub1dmcd5wqd3yku05svp6xqk5gyywek4cgg0w3dk63tcu0rmjxnanns5xutjm, how does nostr:npub1ex7mdykw786qxvmtuls208uyxmn0hse95rfwsarvfde5yg6wy7jq6qvyt9 Bill Pay calculate cost basis for bitcoin deposited from external wallets?