code give numbering to a record

I have three columns
Where in Column B I have a ID.
I want to find first consecutive id and give all same number as “1” in column C
And all rest should be numbered as “2”

For example
a) row2 has id JIOKO2N15069 so it numbered as “1” and then row 20, 21, 22 and 23 has same id hence it numbered as 2 in column c
b) Row3 and 4 has id 07248 it numbered as “1” and then row 6 has same id hence it numbered as 2 in column c
c) Row 7 to 12 and 4 has id JIOV4SV14748 it numbered as “1” and then row 17 and 18 has same id hence it numbered as 2 in column c


Please provide code to give numbering 1 and 2 in column C.

Hi, maybe a formula would be ok?
Try the attachment

Ok with formula. But it is not working. Please refer attachment

i've change the formula in new file