You are given a circular necklace that has m x n beads. Each bead is initially uncoloured. Let $f(m,n)$ denote the number of ways you can assign colours to the necklace beads where each bead can have one of m ($m \ge 2$) colours, using each colour on exactly n beads ($n \ge 1$). 2 Necklaces are considered same if they give the same view after rotating. Find $\sum_{n=2}^{4}\sum_{m=2}^{5}f(m,n)$.