list digit into number

[Voldyy]

Hi, how can i change this code to work for two-digit numbers or three-digit number?

For now only work for single digit numbers, tried to change algorthm but didnt work.

def to_number(digits):
    result=digits[0]
    for el in digits[1:]:
        result=result*10
        result=result + el
    return result

Now the ouput is 2221 - i think is because of this line result=result + el
It has to output this:
input: [ 21, 12, 1]
output: 21121