#include <iostream>
#include <queue>
#include <cmath>
#include <vector>

using namespace std;
const int maxn = 1e5 + 10;

struct node {
    int idx, shortest_path;
    node() {}
    node(int _idx, int _shortest_path) {
        idx = _idx;
        shortest_path = _shortest_path;
    }

    bool operator < (const node & tmp) const {
        return shortest_path > tmp.shortest_path;
    }
};
int main(){
    int n, V;
    cin >> n >> V;

    vector<int> portals(n);
    for(int i = 0; i < n; i++) {
        cin >> portals[i];
    }

    vector<pair<int, int>> graph[maxn];

    for(int i = 0; i < n; i++) {
        if(i + 1 < n) {
            graph[i].push_back(make_pair(i + 1, 1));
        }
        if(i - 1 >= 0) {
            graph[i].push_back(make_pair(i - 1, 1));
        }

        for(int j = 0; j < n; j++) {
            if(portals[i] == portals[j]) {
                graph[i].push_back(make_pair(j, V));
            }
        }
    }

    vector<bool> visited(n, false);
    vector<int> dist(n, 2e9);

    priority_queue<node> pq;
    pq.push(node(0, 0));

    while(!pq.empty()) {
        node c = pq.top();
        pq.pop();

        if(visited[c.idx]) {
            continue;
        }
        visited[c.idx] = true;

        for(int i = 0; i < (int) graph[c.idx].size(); i++) {
            int neighbour = graph[c.idx][i].first;
            int weight = graph[c.idx][i].second;

            if(!visited[neighbour] and c.shortest_path + weight < dist[neighbour]) {
                dist[neighbour] = c.shortest_path + weight;
                pq.push(node(neighbour, dist[neighbour]));
            }
        }
    }

    cout << dist[n - 1] << endl;

    return 0;
}