Dublicates counter

[ATSV1900]

Hello all, 

So what I am trying to build is a formular which generates for every number the value 1 except the number appears more than one time. 

If the Number appears more than one time the system should count the dublicates until a new number appears. 

Please find the table below. 

101	1
101	2
102	1
103	1
104	1
104	2
105	1
106	1
106	2
106	3
107	1

[#2]

@ATSV1900 

Assuming your numbers are in column A starting from A1, put in B1

=COUNTIF($A$1:$A1,A1)

and drag it down