Counting Total excluding Missing Values

Good Afternoon

I need some help with a measure please.

In my data i have the below:

EventCode,  Month,  Person Count

1,                    1 ,          

1,                    2,                 26

1,                    3,                 35

Code is replicated each month, however there is not a count for each month. What i need to do is count the total number of each code where there is a count.

So in the example above the count of code would be 2.