{$APPTYPECONSOLE}
var
  a, b, c, d: integer;
  function max(a,b:integer;):integer;
    begin
      if (a > b) then
        result := a
      else
        result := b;
    end;
begin
  readln (a, b, c, d);
  writeln (max(max(max(a, b), c), d));
  readln;
  readln;
end;