B'You are given a line of n colored squares in a row, numbered from 1 to n from left to right. The i -th square initially has the color c_i . Let 's say, that two squares i and j belong to the same connected component if c_i = c_j , and c_i = c_k for all k satisfying i < k < j . In other words, all squares on the segment from i to j should have the same color. For example, the line [3, 3, 3] has 1 connected component, while the line [5, 2, 4, 4] has 3 connected components. The game "flood fill" is played on the given line as follows: Find the minimum number of turns needed for the entire line to be changed into a single color. The first line contains a single integer n ( 1 <= n <= 5000 ) -- the number of squares. The second line contains integers c_1, c_2, ldots, c_n ( 1 <= c_i <= 5000 ) -- the initial colors of the squares. Print a single integer -- the minimum number of the turns needed. In the first example, a possible way to achieve an optimal answer is to pick square with index 2 as the starting square and then play as follows: In the second example, a possible way to achieve an optimal answer is to pick square with index 5 as the starting square and then perform recoloring into colors 2, 3, 5, 4 in that order. In the third example, the line already consists of one color only. '...