#include <bits/stdc++.h>
#define INF INT_MAX / 2
#define MOD 1000000007

using namespace std;

typedef pair<int,int> PII;
typedef pair<int,pair<int,int>> PIPII;
typedef long long ll;

bool isKadomatsuSequence(int a2,int a1,int a0){
    if((a1 < a0 && a1 < a2 || a1 > a2 && a1 > a0) && a2 != a0)return true;
    return false;
}

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

int m[101][101];
bool used[101][101][11][11];
int memo[101][101][11][11];

int w,h;
int dfs(int y,int x,int prev2,int prev1){
    if(y<0||y>=h||x<0||x>=w|| prev2 != -1 && !isKadomatsuSequence(prev2,prev1,m[y][x]) || used[y][x][prev2+1][prev1+1])return INF;
    if(y == h-1 && x == w-1)return 0;
    if(memo[y][x][prev2+1][prev1+1] != -1)return memo[y][x][prev2+1][prev1+1];
    //cout << y << " " << x << endl;
    int ret = INF;
    for(int i=0;i<4;i++){
        used[y][x][prev2+1][prev1+1] = true;
        ret = min(ret,dfs(y+dy[i],x+dx[i],prev1,m[y][x]));
        used[y][x][prev2+1][prev1+1] = false;
    }
    return memo[y][x][prev2+1][prev1+1] = ret+1;
}

int main(void) {
    cin >> w >> h;
    memset(memo,-1,sizeof(memo));
    for(int i=0;i<h;i++){
        for(int j=0;j<w;j++){
            cin >> m[i][j];
        }
    }
    int ans = dfs(0,0,-1,-1);
    if(ans>=INF)cout << -1 << endl;
    else cout << ans << endl;
}