Consider the graph of \(y = f(x)\) with key points \((-5,-1)\), \((-3,2)\), \((-1,1)\), \((0,3)\), \((2,3)\), \((5,-1)\) and a horizontal asymptote \(y=2\). Find the number of solution(s) of \(x\) satisfying \(f(f(x)) = 2\).
Let R1 = {(p, pn) : p prime, n ≥0, pn ≤50} and R2 = {(p, pn) : p prime, n = 0 or 1} on {1, . . . , 50}. The number of elements in R1 −R2 is: