Limits, Continuity and Differentiability

Let the functions f:(−1,1)→R and g:(−1,1)→(−1,1) be defined byf(x)=|2x−1|+|2x+1| and g(x)=x−[x] ,
where [x] denotes the greatest integer less than or equal to x. Let fog:(−1,1)→R be the composite function defined by (f o g) (x)=f(g(x)). Suppose c is the number of points in the interval (-1,1) at which fog is NOT continuous, and suppose d is the number of points in the interval (-1,1) at which f o g is NOT differentiable. Then the value of c+ d is