How to decrease maxTxAmount via Web3 on BSCScan to match 0.5% of all supply?

Smart Contracts
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1

Hi,
I'm trying to decrease maxTxAmount via Web3 on BSCscan to match 0.5% of all supply.
I tried to input: 0.5 but I'm receiving this error message:

invalid number value (arg="maxTxPercent", coderType="uint256", value="0.5")

Any advice?
Thanks,
Mike