#include "bits/stdc++.h"
using namespace std;
typedef long long ll;

int main() {
    int h, w; cin >> h >> w;
    int a, b, c, d; cin >> a >> b >> c >> d;
    for (int i = 0; i < h; i++) {
        string s; cin >> s;
    }
    cout << abs(a - c) + abs(b - d) << endl;
    return 0;
}