Стройка, нахождение самого большого "дома"

uses Crt;
const max=250;
var
  k:array[1..max] of integer;
  a:array[1..max,1..max] of char;
  n,m:integer;
  s,i,j,e:integer;
  si,sj:integer;
procedure vvod;
var
  ch:char;
begin
  ClrScr;
  Write('Kolichestvo stolbcov : ');Readln(n);
  Write('Kolichestvo strok    : ');Readln(m);
    for i:=1 to n do
    for j:=1 to m do begin
      repeat
       Write('B KBagpaTe (',i,',',j,') ECTb CTpoeHu9 (Yes/No) : ');
       ch:=UpCase(readkey);
       Writeln(ch);
      until (ch='Y') or (ch='N');
      if ch='Y' then a[i,j]:='R' else a[i,j]:='F';
    end;
end;
 
 
BEGIN
  vvod;
  writeln;
  writeln('R-reserved unit');
  writeln('F-free unit');
  writeln('');
  for i:=1 to n do begin
    for j:=1 to m do begin
    write(a[i,j],' ');
    end;
    writeln;
    end;
 For i:=1 to n do
     for j:=1 to m do begin
        If (a[i,j]='F') and (a[i+1,j]<>'R') and (a[i-1,j]<>'R') and
        (a[i,j+1]<>'R') and (a[i,j-1]<>'R') then a[i,j]:='O'; end;
 writeln;
 writeln;
 writeln('O - mesto dla postroiki ');
 writeln;
  for i:=1 to n do begin
    for j:=1 to m do begin
    write(a[i,j],' ');
    end;
    writeln;
    end;
 
readkey;
END.