#include <cstdio>
#include <queue>
#include <algorithm>

using namespace std;

const int MAXN = 512;

struct  vertex{
    int x, y, dist;
    vertex(){}
    vertex ( int _x, int _y, int _dist ) {
        x = _x;
        y = _y;
        dist = _dist;
    }

    bool operator< ( vertex t1 )const {
        return dist > t1.dist;
    }
};

int D[MAXN][MAXN];
int used[MAXN][MAXN];
int N, M, A, B;
char a[MAXN][MAXN];
int dx[] = { 1, 0, -1, 0 };
int dy[] = { 0, -1, 0, 1 };
int sx, sy, fx, fy;
priority_queue <vertex> q;

void scan(){
    scanf ( "%d%d%d%d", &N, &M, &A, &B );

    for ( int i = 0; i < N; ++i )
            scanf ( "%s", a[i] );

    scanf ( "%d%d%d%d", &sx, &sy, &fx, &fy );
}

void dijkstra( int x, int y ){
    for ( int i = 0; i < N; ++i )
        for ( int j = 0; j < M; ++j )
            D[i][j] = 1e9;

    D[x][y] = 0;
    q.push ( vertex ( x, y, 0 ) );

    while ( !q.empty() ){
        vertex t = q.top();
        x = t.x;
        y = t.y;
        q.pop();
        if ( used[x][y] )
            continue;
        used[x][y] = 1;

        for ( int k = 0; k < 4; ++k ){
            int nx = x + dx[k], ny = y + dy[k];
            if ( nx < 0 || ny < 0 || nx >= N && ny >= M )
                continue;
            if ( used[nx][ny] ) continue;

            if ( D[nx][ny] > D[x][y] + B + ( a[x][y] != a[nx][ny] ) * A ){
                D[nx][ny] = D[x][y] + B + ( a[x][y] != a[nx][ny] ) * A ;
                q.push ( vertex ( nx, ny, D[nx][ny] ) );
            }
        }
    }
}

void solve(){
    --sx; --sy; --fx; --fy;

    dijkstra ( sx, sy );

    printf ( "%d\n", D[fx][fy] );
}


int main(){
    freopen ( "exam.in", "r", stdin );
    freopen ( "exam.out", "w", stdout );
    scan();
    solve();
}
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