#include <iostream>
#include <tuple>
#include <functional>
#include <vector>
#include <queue>
using namespace std;

using State = tuple<int, int, int, int>; // (移動回数, 行, 列, 直前の数字)

const int MAX_W = 110;
const int MAX_H = 110;
const int INF = (1 << 28);

int dist[MAX_H][MAX_W][10];
int m[MAX_H][MAX_W];

int dr[4] = {1, 0, -1, 0},
    dc[4] = {0, 1, 0, -1};

int w, h;

bool inside(int r, int c) {
    return 0 <= r && r < h && 0 <= c && c < w;
}

int main() {
    cin >> w >> h;

    for (int r = 0; r < h; r++) {
        for (int c = 0; c < w; c++) {
            cin >> m[r][c];
        }
    }

    for (int r = 0; r < h; r++) {
        for (int c = 0; c < w; c++) {
            for (int d = 0; d < 10; d++) {
                dist[r][c][d] = INF;
            }
        }
    }

    priority_queue<State, vector<State>, greater<State>> que;
    if (m[0][1] != m[0][0]) {
        dist[0][1][m[0][0]] = 1;
        que.push(State(1, 0, 1, m[0][0]));
    }
    if (m[1][0] != m[0][0]) {
        dist[1][0][m[0][0]] = 1;
        que.push(State(1, 1, 0, m[0][0]));
    }
    while (!que.empty()) {
        State s = que.top(); que.pop();
        int cost = get<0>(s),
            row = get<1>(s),
            col = get<2>(s),
            prev = get<3>(s);
        if (dist[row][col][prev] < cost) continue;

        // ゴールできたら終了
        if (row == h - 1 && col == w - 1) {
            cout << cost << endl;
            return 0;
        }

        int cur = m[row][col];
        for (int i = 0; i < 4; i++) {
            int nr = row + dr[i], nc = col + dc[i];
            if (inside(nr, nc)) {
                // 門松列の条件を満たしているか
                int next = m[nr][nc];
                if (prev == next || dist[nr][nc][cur] <= cost + 1) continue;

                if (cur > prev && cur > next) {
                    dist[nr][nc][cur] = cost + 1;
                    que.push(State(cost + 1, nr, nc, cur));
                } else if (cur < prev && cur < next) {
                    dist[nr][nc][cur] = cost + 1;
                    que.push(State(cost + 1, nr, nc, cur));
                }
            }
        }
    }
    cout << -1 << endl;

    return 0;
}