I have about 300 rasters that I need to find the overlap and sum of to find 'hotspots'. I set each raster value to 1 and used the Mosaic to New Raster tool to create a new raster. I tested this with two files (test), the test raster has a value of 2 where the other two rasters overlapped. 

How do I manage to find all the overlapping rasters and add them together in ModelBuilder? 

[![enter image description here][1]][1]

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  [2]: https://i.sstatic.net/v90xN.jpg

  [1]: https://i.sstatic.net/l4dR1.png