count number of instances based on date, but date format is 2/6/2015 14:34:00

Hello. I'm using excel for my report generated from CRM. My crm provides me csv. I'd like to count the number of instances per month, not per day. Each line should be counted as 1. See sample data below:

John 2/6/15 14:34
Walter 4/28/15 10:41
John 6/24/15 11:47
Walter 5/6/15 09:31
Walter 5/6/15 15:35
James 5/13/15 14:16
James 4/22/15 14:48
James 5/15/15 17:22
James 6/5/15 13:42

In sample data above, I'd like to know how many instances did John generate opportunity in Feb, March, April... How many times Walter generated opportunity in Feb, March, April... James also, ...

FYI only, I'd like to count how many opportunities generated by sales in a given month. Each line represents an opportunity generated by the person in the other column. The time of day is irrelevant.

Glenn,

Exactly the way you did it. Thanks. I'll analyze the formula.

Thanks