#include <bits/stdc++.h>
#define rep(i, a) for (int i = 0; i < (a); i++)
#define rep2(i, a, b) for (int i = (a); i < (b); i++)
#define repr(i, a) for (int i = (a) - 1; i >= 0; i--)
#define repr2(i, a, b) for (int i = (b) - 1; i >= (a); i--)
using namespace std;
typedef long long ll;
const ll inf = 1e9;
const ll mod = 1e9 + 7;

int W, H;
int M[111][111];

int dp[111][111][11][11]; // y, x, curr, prev
typedef tuple<int, int, int, int, int> P; // dist, y, x, curr, prev

int main() {
	cin >> W >> H;
	rep (i, H) rep (j, W) cin >> M[i][j];

	rep (i, 111) rep (j, 111) rep (k, 11) rep (l, 11) dp[i][j][k][l] = inf;

	priority_queue<P, vector<P>, greater<P>> q;
	q.emplace(0, 0, 0, M[0][0], 0);
	dp[0][0][M[0][0]][0] = 0;

	while (!q.empty()) {
		P p = q.top(); q.pop();
		int y = get<1>(p);
		int x = get<2>(p);
		int curr = get<3>(p);
		int prev = get<4>(p);

		int dy[] = {0, 1, 0, -1};
		int dx[] = {1, 0, -1, 0};

		rep (k, 4) {
			int ny = y + dy[k];
			int nx = x + dx[k];

			if (ny < 0 || ny >= H || nx < 0 || nx >= W) continue;

			int next = M[ny][nx];

			if (prev == 0) {
				if (curr == next) continue;
				if (dp[ny][nx][next][curr] > dp[y][x][curr][prev] + 1) {
					dp[ny][nx][next][curr] = dp[y][x][curr][prev] + 1;
					q.emplace(dp[ny][nx][next][curr], ny, nx, next, curr);
				}
			} else {
				if (prev == curr || prev == next || curr == next) continue;

				if (prev > curr && curr < next || prev < curr && curr > next) {
					if (dp[ny][nx][next][curr] > dp[y][x][curr][prev] + 1) {
						dp[ny][nx][next][curr] = dp[y][x][curr][prev] + 1;
						q.emplace(dp[ny][nx][next][curr], ny, nx, next, curr);
					}
				}
			}
		}
	}

	int ans = inf;
	rep (k, 10) rep (l, 10) {
		ans = min(ans, dp[H - 1][W - 1][k][l]);
	}
	if (ans == inf) ans = -1;
	cout << ans << endl;

	return 0;
}