round number up in equation. ceil()

hello! 
how to round a number up? this is a duplicate for https://r1132100503382-eu1-3dswym.3dexperience.3ds.com/#community:yUw32GbYTEqKdgY7-jbZPg/post:qK6rcUhBQQC-X7063RZkjQ

 

that is 3 years without answer:(

Thank you for any suggestions.