Olymp_H

gistfile1.pas

var source: string;
    i, k, flag: integer;
    c: char;

begin
readln(source);
for i:= 1 to length(source) do
  begin
    flag:=0;
    for k:= (i+1) to length(source) do
      if (source[i] = source[k]) then
        begin
          flag:= 1;
          break;
        end;
    if (flag = 1) then
      begin
       writeln(source[i]);
       break;
      end;
  end;
end.