#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
using vll = vector<ll>;
using vvll = vector<vector<ll>>;
using P = pair<ll, ll>;
using vp = vector<pair<ll, ll>>;
#define mod 1000000007
#define all(v) v.begin(),v.end()
#define resort(v) sort(v.rbegin(),v.rend())
#define rep(i, n) for (ll i = 0; i < n; ++i)
#define per(i, n) for (ll i = n - 1; i >= 0; --i)
#define rep2(i, a, n) for (ll i = a; i < n; ++i)
#define per2(i, a, n) for (ll i = n - 1; i >= a; --i)
#define chmin(a, b) a = min(a, b)
#define chmax(a, b) a = max(a, b)
const ll inf = 1ll << 60;
ll dx[] = {1, 0, -1, 0, -1, 1, -1, 1};
ll dy[] = {0, 1, 0, -1, -1, 1, 1, -1};

int main() {
    ll h,w;
    cin >> h >> w;
    vvll a(h,vll(w));
    rep(i,h){
        rep(j,w) cin >> a[i][j];
    }
    vvll dist(h,vll(w,-1));
    vector<set<tuple<ll,ll,ll>>> st(2);
    dist[0][0] = 0;
    dist[h-1][w-1] = 1;
    queue<P> q;
    q.push({0,0});
    q.push({h-1,w-1});
    ll i=0,ans=0;
    while (!q.empty()){
        ll x = q.front().first,y = q.front().second;
        q.pop();
        rep(k,4){
            if(x+dx[k]>=0&&y+dy[k]>=0&&x+dx[k]<h&&y+dy[k]<w&&dist[x+dx[k]][y+dy[k]]==-1){
                st[i].insert({a[x+dx[k]][y+dy[k]],x+dx[k],y+dy[k]});
            }
        }
        auto[m,mx,my] = *st[i].begin();
        q.push({mx,my});
        st[i].erase(*st[i].begin());
        dist[mx][my]=i;
        ans++;
        i = 1-i;
        rep(k,4){
            if(mx+dx[k]>=0&&my+dy[k]>=0&&mx+dx[k]<h&&my+dy[k]<w){
                if(dist[mx+dx[k]][my+dy[k]]==i){
                    cout << ans << endl;
                    return 0;
                } 
            }
        }
    }
}