Pairing function that generates the smallest result

I noticed that there are various pairing functions, I tried the cantor pairing function which has a ratio of 150% on the final length: x = 10 chars lenght y = 10 chars lenght CANTOR = 25 chars lenght, while the Szudzik pairing function has a 100% ratio: x = 10 chars length y = 10 chars length Szudzik = 20 chars length, is there another pairing function that has a 0% ratio? x = 10 chars length y = 10 chars length Pairing function = 10 chars length. or in any case some tabular system that allows me to find a large number, with half the characters: 548721 -> 254 (example) Thanks!