#include<iostream>
#include<queue>
#include<cstring>
#define x first
#define y second

using namespace std;

typedef pair<int, int> PII;

const int N = 110;

char g[N][N];
int vis[N][N];
int n,m;
PII start;

int bfs()
{
    memset(vis,-1,sizeof vis);
    queue<PII>q;
    q.push(start);
    vis[start.x][start.y]=0;


    int dx[]={0,1,1,1,0,-1,-1,-1};
    int dy[]={1,1,0,-1,-1,-1,0,1};
    int res = 0;
    while(!q.empty())
    {
        PII t = q.front();
        q.pop();
        for(int i = 0;i<8;i++)
        {
            int x = t.x+dx[i],y = t.y+dy[i];
            if(x<1||x>n||y<1||y>m) continue;
            if(vis[x][y]!=-1) continue;
            if(g[x][y]=='*') continue;
            vis[x][y]=vis[t.x][t.y]+1;
            res = max(res,vis[x][y]);
            q.push({x,y});
        }
    }
    return res;
}

int main()
{
    cin>>m>>n>>start.y>>start.x;

    for(int i = 1;i<=n;i++)
    {
        for(int j = 1;j<=m;j++)
        {
            cin>>g[i][j];
        }
    }
    cout<<bfs()<<endl;
}