#include <bits/stdc++.h>
using namespace std;

typedef long long   signed int LL;
typedef long long unsigned int LU;

#define incID(i, l, r) for(int i = (l)    ; i <  (r); i++)
#define incII(i, l, r) for(int i = (l)    ; i <= (r); i++)
#define decID(i, l, r) for(int i = (r) - 1; i >= (l); i--)
#define decII(i, l, r) for(int i = (r)    ; i >= (l); i--)
#define  inc(i, n) incID(i, 0, n)
#define inc1(i, n) incII(i, 1, n)
#define  dec(i, n) decID(i, 0, n)
#define dec1(i, n) decII(i, 1, n)

#define inII(v, l, r) ((l) <= (v) && (v) <= (r))
#define inID(v, l, r) ((l) <= (v) && (v) <  (r))

#define PB push_back
#define EB emplace_back
#define MP make_pair
#define FI first
#define SE second
#define UB upper_bound
#define LB lower_bound
#define PQ priority_queue

#define  ALL(v)  v.begin(),  v.end()
#define RALL(v) v.rbegin(), v.rend()
#define  FOR(it, v) for(auto it =  v.begin(); it !=  v.end(); ++it)
#define RFOR(it, v) for(auto it = v.rbegin(); it != v.rend(); ++it)

template<typename T> bool   setmin(T & a, T b) { if(b <  a) { a = b; return true; } else { return false; } }
template<typename T> bool   setmax(T & a, T b) { if(b >  a) { a = b; return true; } else { return false; } }
template<typename T> bool setmineq(T & a, T b) { if(b <= a) { a = b; return true; } else { return false; } }
template<typename T> bool setmaxeq(T & a, T b) { if(b >= a) { a = b; return true; } else { return false; } }
template<typename T> T gcd(T a, T b) { return (b == 0 ? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }

// ---- ----

int w, h, m[100][100];
vector<pair<int, int>> v[40000];
int d[40000], INF = 40000;

template<typename T> class RPQ : public PQ<T, vector<T>, greater<T>> { };
template<typename Cost> void dijkstra(int start, vector<pair<int, Cost>> g[], Cost dist[]) {
	RPQ<pair<Cost, int>> q;
	dist[start] = 0;
	q.emplace(dist[start], start);
	while(! q.empty()) {
		auto cp = q.top(); q.pop();
		int  p = cp.SE;
		Cost c = cp.FI;
		if(dist[p] != c) { continue; }
		for(auto && e : g[p]) {
			int  ep = e.FI;
			Cost ec = e.SE;
			if(setmin(dist[ep], dist[p] + ec)) { q.emplace(dist[ep], ep); }
		}
	}
	return;
}

bool f(int a, int b, int c) {
	return ((a < b && b > c) || (a > b && b < c)) && (a != c);
}

int main() {
	cin >> w >> h;
	inc(i, h) {
	inc(j, w) {
		cin >> m[i][j];
	}
	}
	
	int s = 0 + 2;
	int g = 0 + 3;
	v[s].EB((0 * w + 1) * 4 + 2, 1);
	v[s].EB((1 * w + 0) * 4 + 3, 1);
	v[(h * w - 1) * 4 + 2].EB(g, 0);
	v[(h * w - 1) * 4 + 3].EB(g, 0);
	inc(i, h) {
	inc(j, w) {
		int di[4] = { 0, 1,  0, -1 };
		int dj[4] = { 1, 0, -1,  0 };
		inc(k, 4) {
		inc(l, 4) {
			int ki = i + di[k];
			int kj = j + dj[k];
			int li = i + di[l];
			int lj = j + dj[l];
			if(! (inID(ki, 0, h) && inID(kj, 0, w))) { continue; }
			if(! (inID(li, 0, h) && inID(lj, 0, w))) { continue; }
			
			int p = ( i * w +  j) * 4 + k;
			int q = (li * w + lj) * 4 + (l + 2) % 4;
			v[p].EB(q, (f(m[ki][kj], m[i][j], m[li][lj]) ? 1 : INF));
		}
		}
	}
	}
	
	inc(i, h * w * 4) { d[i] = INF; }
	dijkstra(s, v, d);
	
	cout << (d[g] < INF ? d[g] : -1) << endl;
	
	return 0;
}