Let $x+y=0$ be the radical axis of the circles $\mathrm{S} \equiv x^2+y^2$ $+2 g x+2 f y+c=0$ and $\mathrm{S}^1 \equiv x^2+y^2-6 x-4 y+4=0$ and the radius of the circle $\mathrm{S}=0$ be 1 . The $g+f=$