In ArcGIS 10.2 I have 2 rasters A and B. A cover a certain study area while B represent a "cities mask" obtained by rasterising a shapefile. All the cells of B have a 0 value. The resolution of A and B is the same. I simply want A's cells to have a value of 0 when they match with B's cells. I have tried using the conditional function in the raster calculator [ Con(B=0,"B","A")] and setting A as "snap raster" in the environmental settings, but the output raster is always equal to B. I also tried to multiply AxB setting A as "snap raster" but again the result is B. What am I doing wrong?