So we open up our parentheses. So this becomes negative and this becomes negative. And we also want to replace MDIS with the following representation. So, we have the mass multiplied by the density of the fluid multiplied by V bar, which is simply one over the density of the particle multiplied by omega squared multiplied by R minus FV. And the minus comes because we open up those parentheses and we set that equal to zero. So this is a bit crooked.