const n=10;
var
 a,c:array[1..n] of integer;
 k,i,j,m,Nc:integer;
 b:boolean;

begin
 for i:=1 to n do
  begin
   Write('a[',i:2,']= ');
   Readln(a[i]);
  end;

 Nc:=0;

 for i:=1 to n do
  begin
   k:=0;
   for j:=1 to n do
    if a[i]=a[j] then k:=k+1;
   if k>=2 then
    begin
     b:=true;
     for m:=1 to Nc do
      if a[i]=c[m] then b:=false;
     if b then
      begin
       Nc:=Nc+1;
       c[Nc]:=a[i];
      end;
    end;
  end;

 for m:=1 to Nc do WriteLn(c[m]);

 Readln;
end.