#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>

using namespace std;
using ll = long long;

struct pont
{
	int x, y;
};

pont operator -(pont A, pont B)
{
	return { A.x - B.x, A.y - B.y };
}

pont operator +(pont A, pont B)
{
	return { A.x + B.x, A.y + B.y };
}

int sgn(int x) {
	return x > 0 ? 1 : x < 0 ? -1 : 0;
}

int irany(pont A, pont B)
{
	return sgn((ll)A.x * B.y - (ll)A.y * B.x);
}

int irany(pont A, pont B, pont C)
{
	return irany(A - C, B - C);
}

double hossz(pont A)
{
	return sqrt((double)A.x * A.x + (double)A.y * A.y);
}

int main()
{
	ios::sync_with_stdio(false);
	int W, H;
	pont S, E;
	cin >> W >> H >> S.x >> S.y >> E.x >> E.y;
	vector<vector<int>> T(W / 2, vector<int>(H / 2));
	for (int i = 0; i < H / 2; i++)
	{
		for (int j = 0; j < W / 2; j++)
		{
			cin >> T[j][i];
		}
	}
	if (S.y > E.y)
		swap(S, E);
	if (S.x > E.x)
	{
		reverse(T.begin(), T.end());
		S.x = W - S.x;
		E.x = W - E.x;
	}
	pont poz = S;
	int koltseg = 0;
	while (poz.x != E.x || poz.y != E.y)
	{
		int ir = irany(S, E, poz + pont{ 1, 1 });
		int i = poz.x / 2;
		int j = poz.y / 2;
		if (ir == 1)
		{
			koltseg += abs(T[i][j] - T[i + 1][j]);
			poz.x += 2;
		}
		else if (ir == -1)
		{
			koltseg += abs(T[i][j] - T[i][j + 1]);
			poz.y += 2;
		}
		else
		{
			int h = min(T[i + 1][j], T[i][j + 1]);
			if (h > max(T[i][j], T[i + 1][j + 1]))
				koltseg += 2 * h - T[i][j] - T[i + 1][j + 1];
			else
				koltseg += abs(T[i][j] - T[i + 1][j + 1]);
			poz = poz + pont {2, 2};
		}
	}
	cerr << "koltseg = " << koltseg << "\n";
	cout.precision(20);
	cout << koltseg + hossz(E - S) << "\n";
}