Conditional Range sum formula

Hi,

I am trying to create a conditional sum.

My data is as the example bellow (but with a much large data, 350.000 lines)


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A B C

1 Year Month Value
2 2014 03 5
3 2014 02 5
4 2014 01 3
5 2013 12 4
6 2013 11 8
7 2013 01 2
8 2012 10 5
9 2012 09 7
10 2011 12 6
11 2011 01 4



What I need is to add the values for the dates in the range of 2012/10 and 2014/02 (including those months), so the total would be 27.

I’ve tried sumif and sum(if()), but couldn’t do it, hope someone could help me.

My data have more columns as well, but with much easier criteria to filter (sumifs solves it easially), my problem is filtering this conditioning with the conditional range.