How to set the desired photo size when printing on canon selphy?

Question

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Actually there is a cp720 printer and a Nikon d90 camera.
It is necessary to print an image with a size of 74x49mm. Is it possible to do this only with the help of a camera and a printer, or is it impossible to do without a computer? And are there ways to crop a printed photo quickly without scissors or a knife? Who has any ideas.