#include <iostream>
#include <vector>
#include <limits>

using namespace std;

struct State {
	int x;
	int y;
	int previousValue;
	int steps;
	State(int x, int y, int previousValue, int steps) :
		x(x), y(y), previousValue(previousValue), steps(steps) {
	}
};

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

bool isKadomatsuSequence(int a, int b, int c) {
	if (a < 0 || b < 0 || c < 0) {
		return true;
	}
	if (a != c) {
		if (a < b && b > c) {
			return true;
		}
		if (a > b && b < c) {
			return true;
		}
	}
	return false;
}

int main() {
	int w, h;
	cin >> w >> h;
	vector<vector<int> > m(w, vector<int>(h));
	for (int y = 0; y < h; ++y) {
		for (int x = 0; x < w; ++x) {
			cin >> m[x][y];
		}
	}
	vector<State> states;
	vector<vector<int> > shortest(w, vector<int>(h, numeric_limits<int>::max()));
	states.push_back(State(0, 0, -1, 0));
	shortest[0][0] = states.back().steps;
	while (!states.empty()) {
		State top = states.back();
		states.pop_back();
		int topValue = m[top.x][top.y];
		for (int d = 0; d < 4; ++d) {
			State next(top.x + dx[d], top.y + dy[d], topValue, top.steps + 1);
			if (0 <= next.x && next.x < w 
				&& 0 <= next.y && next.y < h
				&& isKadomatsuSequence(top.previousValue, topValue, m[next.x][next.y])
				&& next.steps < shortest[next.x][next.y]) {
				shortest[next.x][next.y] = next.steps;
				if (next.x != w - 1 || next.y != h - 1) {
					states.push_back(next);
				}
			}
		}
	}
	cout << (
		shortest[w - 1][h - 1] == numeric_limits<int>::max() 
		? -1 
		: shortest[w - 1][h - 1]
		) << endl;
	return 0;
}