Let r₁, r₂ be the radii of the largest and smallest circles respectively passing through the point (-4,1) and having their centres on the circumference of the circle $x^2+y^2+2x+4y-4=0$ if $\frac{{\text{r}}_{\text{1}}}{{\text{r}}_{\text{2}}}\text{=a+b}\sqrt{\text{2}}$ then a+b=__