Customer with One event count per channel

[Sujayrsp]

Hi All,

I have a data set containing  resembling below table.

Channel	Event	Cust
1	X	A
1	X	B
1	Y	C
1	Z	D
1	Q	A
2	Z	A
3	Z	B
4	X	D
1	W	E

The requirement is to get the count of customers having only one event per channel.

for example, here for channel1 ,we have 4 Customers having only one event( B,C ,D,E). so the count is 4.

I have to apply the logic for large data set to get this output.

waiting for your responses.