/** gnu specific **/
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
/** contains everything I need in std **/
#include <bits/stdc++.h>

#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(S) ((int)S.size())
#define FOR(i, st_, n) for(int i = st_; i < n; ++i)
#define RFOR(i, n, end_) for(int i = (n)-1; i >= end_; --i)
#define x first
#define y second
#define pb push_back
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef pair<double, double> pdd;
typedef unsigned long long ull;
typedef long double LD;
typedef pair<ull, ull> pull;
using namespace __gnu_pbds;
typedef tree<ll, null_type, less<>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
using namespace std;
#ifdef ONPC
mt19937 rnd(228);
#else
mt19937 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
#endif


int solve()
{
	int n,m;
	if(!(cin>>n>>m))
		return 1;
	vector<vector<ll>> a(n,vector<ll>(m));
	FOR(i,0,n)FOR(j,0,m)cin>>a[i][j];
	
	int ctr=0;
	{
		set<ll> S;
		FOR(i,0,n)FOR(j,0,m)S.insert(a[i][j]);
		unordered_map<ll,ll> I;
		for(auto item:S)I[item]=ctr++;
		FOR(i,0,n)FOR(j,0,m)a[i][j]=I[a[i][j]];
	}
	set<int> initial;
	FOR(i,0,m)initial.insert(a[0][i]);
	assert(sz(initial)<=2);

	vector<vector<pii>> I(ctr);
	FOR(i,0,n)FOR(j,0,m)I[a[i][j]].pb({i,j});

	vector<int> Dbot(ctr,1e8);
	{
		queue<int> Q;
		FOR(i,0,m) if(Dbot[a[n-1][i]]==1e8) Dbot[a[n-1][i]]=1, Q.push(a[n-1][i]);
		
		while(!Q.empty())
		{
			auto v = Q.front();
			Q.pop();
			for(auto [x,y]: I[v])
			{
				if(x-1>=0&& Dbot[a[x-1][y]]==1e8)
				{
					Dbot[a[x-1][y]]=Dbot[v]+1;
					Q.push(a[x-1][y]);
				}
			}
		}
	}
	
	int u = *initial.begin();
	int v = *initial.rbegin();
	if(u==v)
	{
		cout << Dbot[u]<<'\n';
		return 0;
	}
	
	auto Du = vector<int>(ctr,1e8);
	auto Dv = vector<int>(ctr,1e8);

	Du[u]=0, Dv[v]=0;

	{
		queue<int> Q;
		Q.push(u);
		while(!Q.empty())
		{
			auto vert=Q.front();
			Q.pop();
			
			for(auto [x,y]: I[vert])
			{
				if(x+1<n)
				{
					int to=a[x+1][y];
					if(Du[to]==1e8)
					{
						Du[to]=Du[vert]+1;
						Q.push(to);
					}
				}
			}
		}
	}
	{
		queue<int> Q;
		Q.push(v);
		while(!Q.empty())
		{
			auto vert=Q.front();
			Q.pop();
			
			for(auto [x,y]: I[vert])
			{
				if(x+1<n)
				{
					int to=a[x+1][y];
					if(Dv[to]==1e8)
					{
						Dv[to]=Dv[vert]+1;
						Q.push(to);
					}
				}
			}
		}
	}
	int res=Dbot[u]+Dbot[v];
	FOR(i,0,ctr)
	{
		if(Du[i]!=1e8&&Dv[i]!=1e8)
		{
			res=min(res,Du[i]+Dv[i]+Dbot[i]);
		}
	}
	cout<<res<<'\n';
    return 0;
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    int TET = 1e9;
    //cin >> TET;
    for (int i = 1; i <= TET; i++)
    {
        if (solve())
        {
            break;
        }
#ifdef ONPC
        cout << "__________________________" << endl;
#endif
    }
#ifdef ONPC
    cerr << endl << "finished in " << clock() * 1.0 / CLOCKS_PER_SEC << " sec" << endl;
#endif
}