use std::collections::VecDeque;

fn main() {
    let (W, H): (i32, i32) = {
        let mut line: String = String::new();
        std::io::stdin().read_line(&mut line).unwrap();
        let mut iter = line.split_whitespace();
        (
            iter.next().unwrap().parse().unwrap(),
            iter.next().unwrap().parse().unwrap(),
        )
    };

    let mut map=vec![Vec::new();H as usize];

    for i in 0..H{

        let a: Vec<i64> = {
            let mut line: String = String::new();
            std::io::stdin().read_line(&mut line).unwrap();
            line.split_whitespace()
                .map(|x| x.parse().unwrap())
                .collect()
        };

        map[i as usize]=a;
    }

    let mut dp=vec![vec![vec![(1 as i64) <<60;12];W as usize];H as usize];
    let mut q:VecDeque<(i32,i32,i32)>=VecDeque::new();
    let dx: [i32; 4] = [-1, 0, 1, 0];
    let dy: [i32; 4] = [0, -1, 0, 1];

    for i in 0..11{
        dp[0][0][i]=0;
        q.push_back((0,0,(i as i32)));
    }

    while q.len()>0{
        let (x0,y0,a)=q.pop_front().unwrap();

        for i in 0..4{
            let x:i32 = x0 as i32 +dx[i];
            let y:i32 = y0 as i32 +dy[i];

            if 0<=x && x<H && 0<=y && y<W{
                let b=map[x0 as usize][y0 as usize] as i32;
                let c=map[x as usize][y as usize] as i32;

                if a!=b && a!=c && b!=c && ((a<b && b>c) || (a>b && b<c)){
                    if dp[x as usize][y as usize][b as usize]>dp[x0 as usize][y0 as usize][a as usize]+1{
                        dp[x as usize][y as usize][b as usize]=dp[x0 as usize][y0 as usize][a as usize]+1;
                        q.push_back((x,y,b))
                    }
                }

            }
        }
    }

    let mut ans=1<<60;

    for i in 1..10{
        let k =dp[H as usize-1][W as usize-1][i];

        if ans>k{
            ans=k;
        }
    }

    if (ans==1<<60){
        println!("{}",-1);
    }
    else{
        println!("{}",ans);
    }


}