Get minimum value after HLOOKUP

I have a lookup table like so:

a  b  c  d
1  2  3  4

and a row filled with values a, b, c or d, for example:

d  b  b  d  c

I would like to get the minimum value after doing the lookup with the table in a single formula. Something like MIN(HLOOKUP(...)). In the example above, the result would be 2.

I know that I could create a new row with the HLOOKUP and later do a MIN on this row. But in my real case, I have several rows and several lookup tables and I would like to avoid having many intermediate rows.

Do you have any idea?