// ﾅﾆｿﾚｲﾐﾜｶﾝﾅｲ

#include <cstdio>
#include <queue>
#include <algorithm>

class counter_iterator{
private:
    int count;
public:
    counter_iterator() : count(0){}
    counter_iterator(int n) : count(n){}
    bool operator==(const counter_iterator& rhs) const{
        return count == rhs.count;
    }
    bool operator!=(const counter_iterator& rhs) const{
        return count != rhs.count;
    }
    int& operator*(){
        return count;
    }
    counter_iterator& operator++(){
        ++count;
        return *this;
    }
};

class loop{
private:
    int b, e;
public:
    loop(int m) : b(0), e(m){}
    loop(int n, int m) : b(n), e(m){}
    counter_iterator begin() const{
        return counter_iterator(b);
    }
    counter_iterator end() const{
        return counter_iterator(e);
    }
};

inline long long index(int t, int x, int y, int p1, int p2){
    return 1ll * x + 101ll * (y + 101 * (p1 + 10 * (p2 + 10 * t)));
}

inline bool isKadomatsu(int a, int b, int c){
    if(a == b || b == c || c == a){return false;}
    if(b != std::max({a, b, c}) && b != std::min({a, b, c})){return false;}
    return true;
}

int dx[4] = {-1, 1, 0, 0}, dy[4] = {0, 0, -1, 1};
int d[100][100][10][10];

int main(){
    int W, H;
    scanf("%d %d", &W, &H);

    int map[100][100];
    for(int i=0;i<H;i++){
        for(int j=0;j<W;j++){
            scanf("%d", &map[i][j]);
        }
    }

    for(int i : loop(W)){
        for(int j : loop(H)){
            for(int k : loop(10)){
                for(int l : loop(10)){
                    d[i][j][k][l] = 252521;
                }
            }
        }
    }
    
    std::queue<long long> q;
    q.push(index(0, 0, 0, 0, map[0][0]));
    d[0][0][0][map[0][0]] = 0;

    while(!q.empty()){
        long long idx = q.front(); q.pop();
        int x = idx%101,
            y = idx/101%101,
            p1 = idx / 101 / 101 % 10,
            p2 = idx / 101 / 101 / 10 % 10,
            t = idx / 101 / 101 / 10 / 10;

        if(x == W-1 && y == H-1){printf("%d\n", t); return 0;}
        if(t == 25252){break;}
        
        for(int i=0;i<4;i++){
            int nx = x + dx[i], ny = y + dy[i];
            if(0 <= nx && nx < W && 0 <= ny && ny < H){

            }else{
                continue;
            }

            if((t < 1 || isKadomatsu(p1, p2, map[ny][nx])) && t+1 < d[nx][ny][p2][map[ny][nx]]){
                q.push(index(t+1, nx, ny, p2, map[ny][nx]));
                d[nx][ny][p2][map[ny][nx]] = t+1;
            }
        }
    }
    puts("-1");
}