#include <iostream>
#include <list>
#include <climits>
#include <cstdio>

using namespace std;

struct node {
    int node_number;
    int cost;
};

void create_graph ( int r , int c , list<struct node *> * list_ ) {
    int a = r * 8 + c;

    int n , m;

    n = r + 2; m = c + 1;
    if ( n >= 0 && n <= 7 && m >= 0 && m <= 7 ) {
        struct node * nd = new struct node;
        nd->node_number = n*8 + m;
        nd->cost = r*n + c*m;
        list_[a].push_back(nd);
    }
    n = r + 2; m = c - 1;
    if ( n >= 0 && n <= 7 && m >= 0 && m <= 7 ) {
        struct node * nd = new struct node;
        nd->node_number = n*8 + m;
        nd->cost = r*n + c*m;
        list_[a].push_back(nd);
    }
    n = r - 2; m = c + 1;
    if ( n >= 0 && n <= 7 && m >= 0 && m <= 7 ) {
        struct node * nd = new struct node;
        nd->node_number = n*8 + m;
        nd->cost = r*n + c*m;
        list_[a].push_back(nd);
    }
    n = r - 2; m = c - 1;
    if ( n >= 0 && n <= 7 && m >= 0 && m <= 7 ) {
        struct node * nd = new struct node;
        nd->node_number = n*8 + m;
        nd->cost = r*n + c*m;
        list_[a].push_back(nd);
    }
    n = r + 1; m = c + 2;
    if ( n >= 0 && n <= 7 && m >= 0 && m <= 7 ) {
        struct node * nd = new struct node;
        nd->node_number = n*8 + m;
        nd->cost = r*n + c*m;
        list_[a].push_back(nd);
    }
    n = r + 1; m = c - 2;
    if ( n >= 0 && n <= 7 && m >= 0 && m <= 7 ) {
        struct node * nd = new struct node;
        nd->node_number = n*8 + m;
        nd->cost = r*n + c*m;
        list_[a].push_back(nd);
    }
    n = r - 1; m = c + 2;
    if ( n >= 0 && n <= 7 && m >= 0 && m <= 7 ) {
        struct node * nd = new struct node;
        nd->node_number = n*8 + m;
        nd->cost = r*n + c*m;
        list_[a].push_back(nd);
    }
    n = r - 1; m = c - 2;
    if ( n >= 0 && n <= 7 && m >= 0 && m <= 7 ) {
        struct node * nd = new struct node;
        nd->node_number = n*8 + m;
        nd->cost = r*n + c*m;
        list_[a].push_back(nd);
    }

}

int dijkstra ( int s , int t , list<struct node *> *list_ ) {

    int dist[64];
    int visited[64];

    for ( int i = 0 ; i < 64 ; i++ ) {
        dist[i] = INT_MAX;
        visited[i] = 0;
    }

    dist[s] = 0;

    while ( s != -1 ) {

        visited[s] = 1;

        for ( list<struct node *>::iterator itr = list_[s].begin() ; itr != list_[s].end() ; itr++ ) {
            struct node * v = (*itr);
            if ( visited[v->node_number] == 1 )
                continue;

            if ( dist[v->node_number] > dist[s] + v->cost ) {
                dist[v->node_number] = dist[s] + v->cost;
            }
        }

        s = -1;
        int min_distance = INT_MAX;
        for ( int i = 0 ; i < 64 ; i++ ) {
            if ( visited[i] == 0 && dist[i] < min_distance ) {
                s = i;
                min_distance = dist[i];
            }
        }

    }

    return dist[t];

}

int main ( int argc , char * argv[] ) {

    list<struct node *> * list_ = new list<struct node *>[64];

    for ( int i = 0 ; i < 8 ; i ++ ) {
        for ( int j = 0 ;  j < 8 ; j++ ) {
            create_graph( i , j , list_ );
        }
    }

    /*for ( int i = 0 ; i < 64 ; i++ ) {
        cout << "Node " << i << " : ";
        for ( list<struct node *>::iterator itr = list_[i].begin() ; itr != list_[i].end() ; itr++ ) {
            cout << " " << (*itr)->node_number;
        }
        cout << endl;
    }*/

    int r1,c1,r2,c2;
    while ( scanf("%d%d%d%d" , &r1 , &c1 , &r2 , &c2 ) != EOF ) {
        cout << dijkstra ( r1 * 8 + c1 , r2 * 8 + c2 , list_ ) << endl;
    }

    return 0;
}