SASS how to write code correctly?

Question

Sass

Hello, please tell me how to correctly write the following codes in SASS?
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1) I would like to glue input and class in this way

.block
    input.block__element

For some reason, the option with the following view does not work:

.block
    input&__element

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2) How to reach the parent block element, if you are in a child?
I understand that you can move it to the left, but there are cases when you need to put it this way and I would like the .block name to be hooked to element2

.block
    &__element1
        .block__element2