i have the following regex expression `^(([0-9]{1,2})|100|888|777|999)$`

this allows someone to enter the digits: 0-99, 100, 888, 777, 999

I now have to alter the expression to allow: 1-99, 100, 888, 777, 999 (essentially ZERO is not allowed now)

I thought of doing `^(!0|([0-9]{1,2})|100|888|777|999)$` ... but this of course won't work because that would be like saying "if it isn't zero, we are fine"

Any advice?