uses

  Crt;

type

  grade = 0..110;

var

  alpha,

  bravo,

  charlie,

  delta: grade;

  echo: byte;

  ave: real;

begin

  clrscr;

  for echo := 1 to 3 do

    begin

      readln(alpha, bravo, charlie, delta);

      ave := (alpha + bravo + charlie + delta) / 4;

      writeln(ave);

      readln;

    end;

end.