Integration Services :: Import Flat File Which Has Changing Column Order Using SSIS?

I have a flat with few columns

FirstName, lastName, Address
f1,l1,a1
f2,l2,a2

I build my SSIS package based on the above file.But now i receive files with different columns order let say

lastName,FirstNamr,Address
l1,f1,a1
L2,f2,a2
or
Address,FirstName,LastName
a1,f1,l1
a2,f2,l2

every time i receive multiple files in different order and i have to remap all my mappings. These are just a few columns and i have like 20 columns and the order can potentially change any time. so every time i have build new packages remap them etc.

through normal c# code it pretty easy. I tried to add script here but the script also needs a source and mapping so there is also a mapping issue. Is there a better way to do this.