Var
 f1,f2:file of Integer;
 f3:Text;
 a,b,c,Max:Integer;
 i,Imax:Byte;
 Am:Real;
Begin
 Randomize;
 Assign(f1,'xxx');
 Rewrite(f1);
 For i:=1 to 12 do
  begin
   a:=50-Random(100);
   write(f1,a);
   write(a:4);
  end;
 Close(f1);
 Writeln;
 Writeln;
 Reset(f1);
 Assign(f2,'yyy');
 Rewrite(f2);
 For i:=1 to 12 do
  begin
   read(f1,a);
   if (i<6) or (i>8) then
    begin
     write(f2,a);
     write(a:4);
    end;
  end;
 Close(f1);
 Close(f2);
 Reset(f2);
 Rewrite(f1);
 For i:=1 to 9 do
  begin
   read(f2,a);
   write(f1,a);
  end;
 Close(f1);
 Close(f2);
 Erase(f2);
 Writeln;
 Writeln;
 Max:=-60;
 Reset(f1);
 For i:=1 to 9 do
  begin
   read(f1,a);
   if a>Max then
    begin
     Imax:=i;
     Max:=a;
    end;
  end;
 Reset(f1);
 Assign(f3,'zzz.txt');
 Rewrite(f3);
 If Imax=1 then
  begin
   writeln(f3,Max:4);
   writeln(Max:4);
   Am:=1.0*Max;
  end
 else
 If Imax=2 then
  begin
   read(f1,b);
   read(f1,c);
   Writeln(f3,b:4,c:4);
   Writeln(b:4,c:4);
   Am:=(b+c)/2;
  end
 else
  begin
   for i:=1 to Imax-2 do read(f1,a);
   read(f1,b);
   read(f1,c);
   Writeln(f3,a:4,b:4,c:4);
   Writeln(a:4,b:4,c:4);
   Am:=(a+b+c)/3;
  end;
 Close(f1);
 Writeln(f3,'Arithmetic mean: ',Am:0:3);
 Close(f3);
 Writeln('Arithmetic mean: ',Am:0:3);
 Readln
End.