Z80 Assembler, 50 bytes
org 256
ld de,m
ld c,9
jp 5
m:db"Hello, world!\r$"
With assembler there's usually the problem which machine or operating system the program is for. I've chosen CP/M ...
Python 3, 60 59 bytes
D=input();m=int(max(D),16);print(m and int(D,m+1)or len(D))
Quite straight forward implementation.
Input string is assigned to D.
m is the the max() letter in D conver...
Python 3, 63 bytes
print(str(eval(f"({input().replace(' ',')*(')})")).strip("()"))
Try it online!
Similar to hyper-neutrino's answer. Doesn't replace i by j and back, and uses f-string instea...
Python, 205 bytes
Coding the string with the substrings as base 95 number is the shortest I get with this approach:
n=0
for c in"),|9'OJ#SdHlCSD(LqRhc.|)_#s]`N:?foSIb*.BJVa=AH^).&&w*e(&l...
