How to take number of bytes transmitted and received from /net/proc/dev

I want to take the number of bytes transmitted and received from /proc/net/dev in this format: num_ofbytesTransmitted,num_ofbytesReceived. This was my approach: cat /net/proc/dev | grep enp0s3 | cut -f5 -d' ' and cat /net/proc/dev | grep enp0s3 | cut -f48 -d' ' but the problem here is that I can't always use these constants on cut since the numbers can get big and that number has to change... What can I do in these circumstances?