Excel compare two columns in different sheets return value from third cell

I have two sheets

SHEET A contains more than 1500 entries like this

    A       B      C 
  Year   Month  Births  
  1880     1     530  
  1880     2     456  
  1880     3     234     
  1890     1     163     
  1890     2     123     
  1890     3     125     

Sheet 2 is similar but column C has no entries and there are only a few years and months in random years and months:

    A       B      C 
  Year   Month  Births  
  1880     1        
  1890     2               
  1890     3          

I am trying to find a formula to return the value from Sheet 1 | column C to Sheet 2 | column C if column A and B in Sheet 1 are the same as in column A and B in sheet 2.

I am looking for a formula, no VBA since I can't always use it.

And been unable to adapt anything I find here at stackoverflow.

thx