Bead Necklace

**Description:** A necklace of n beads (n >= 2) in a circle; bead i has color c[i] (1..100). Count the adjacent pairs (including bead n next to bead 1) with DIFFERENT colors. **Input:** Line 1: n (2 <= n <= 100000). Line 2: n integers c[i]. **Output:** One integer — the number of color-changing adjacencies. **Example:** 4 / 1 2 2 1 -> 2 (1-2 and 1-2 across the closure).