Based on the below $10-$K filing, what amount $($in $ million$)$ of its accounts receivables $($both current and long$-$term$)$ is estimated as uncollectible as of June $30,2021$

As of June $30,2021$ and $2020,$ other receivables due from suppliers were $$965$ million and $$442$ million, respectively, and are included in accounts receivable, net in our consolidated balance sheets. As of June $30,2021$ and $2020,$ long$-$term accounts receivable, net of allowance for doubtful accounts, was $$3\mathrm{.}4$ billion and $$2\mathrm{.}7$ billion, respectively, and is included in other long$-$term assets in our consolidated balance sheets. The allowance for doubtful accounts reflects our best estimate of probable losses inherent in the accounts receivable balance. We determine the allowance based on known troubled accounts, historical experience, and other currently available evidence. $64$ PART II Item $8$ Activity in the allowance for doubtful accounts was as follows: $($In millions$)$ Year Ended June $30,202120202019$ Balance, beginning of period $ $816$ $ $434$ $ $397$ Charged to costs and other $234560153$ Write$-$offs $(252)(178)(116)$ Balance, end of period $ $798$ $ $816$ $ $434$ Allowance for doubtful accounts included in our consolidated balance sheets: $($In millions$)$ June $30,202120202019$ Accounts receivable, net of allowance for doubtful accounts $ $751$ $ $788$ $ $411$ Other long$-$term assets $472823$ Total $ $798$ $ $816$ $ $434$