/OCSE - Ốc sên ăn rau

              Uses Crt;
        Var n,m,y,x,i,j,dem:longint;
            a:array[0..101,0..101] of longint;
        Procedure OS(y,x:longint);
        begin
            if a[y,x]=0 then
             begin
                 inc(dem);
                 a[y,x]:=1;
             end;
            if (a[y-1,x]=0) and (y-1>=1) then OS(y-1,x);
            if (a[y+1,x]=0) and (y+1<=n) then OS(y+1,x);
            if (a[y,x-1]=0) and (x-1>=1) then OS(y,x-1);
            if (a[y,x+1]=0) and (x+1<=m) then OS(y,x+1);
        end;
        Begin
            readln(n,m,y,x);
            for i:=1 to n do
             for j:=1 to m do
              read(a[i,j]);
            dem:=0;
            OS(y,x);
            writeln(dem);
            readln;
        End.