Hi @gogi100,
Per my test, you can use MID to extract the numbers and use CONCATENATE to connect string and the calculate result, please refer to following formula
CONCATENATE("Г: ",MID(Column1,3,2)+MID(Column2,3,2),"М: ",MID(Column1,7,2)+MID(Column2,7,2),"Д: ",MID(Column1,13,2)+MID(Column2,13,2))
Here is a nice article about this issue
https://stackoverflow.com/questions/23494276/sharepoint-calculated-field-get-number-only
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