for the reaction, determine the number of transferring electrons so then i can pug into G=-nFE

I'm assigning charges to each of the elements

H2O2(aq) + 2ClO2(g) → O2(g) + 2HClO2(aq)
(+1,-1) + (+4,-2) (0) (+1,+1,-2)

since O changes from -1 to 0, so it lost one electron but Cl gains 3 electrons, so I'm confused is it a total of 3 electrons that are being transferred?