Is it ‘くださいました’ or ‘くださりました’?

According to the rule for turning a Godan verb into masu form, we just need to change ‘くださる’ to ‘くださ**り**’ + ‘ます’, so it seems that it should be ‘くださ**り**ました’.

But I saw this sentence:

>先生は私に日本のおみやげを***くださいました***。

I’m so confused.

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