MODULE BS;

  IMPORT Out;

  VAR
    List:ARRAY 10 OF REAL;

  PROCEDURE Init(VAR List:ARRAY OF REAL);
  BEGIN
    List[0] := -31; List[1] := 0; List[2] := 1; List[3] := 2;
    List[4] := 2; List[5] := 4; List[6] := 65; List[7] := 83;
    List[8] := 99; List[9] := 782;
  END Init;

  PROCEDURE BinarySearch(List:ARRAY OF REAL;Element:REAL):LONGINT;
    VAR
      L,M,H:LONGINT;
  BEGIN
    L := 0;
    H := LEN(List)-1;
    WHILE L <= H DO
      M := (L + H) DIV 2;
      IF List[M] > Element THEN
	H := M - 1;
      ELSIF List[M] < Element THEN
	L := M + 1;
      ELSE
	RETURN M;
      END;
    END;
    RETURN -1;
  END BinarySearch;

  PROCEDURE RBinarySearch(VAR List:ARRAY OF REAL;Element:REAL;L,R:LONGINT):LONGINT;
    VAR
      M:LONGINT;
  BEGIN
    IF R < L THEN RETURN -1 END;
    M := (L + R) DIV 2;
    IF Element = List[M] THEN
      RETURN M
    ELSIF Element < List[M] THEN
      RETURN RBinarySearch(List, Element, L, R-1)
    ELSE
      RETURN RBinarySearch(List, Element, M-1, R)
    END;
  END RBinarySearch;

BEGIN
  Init(List);
  Out.Int(BinarySearch(List, 2), 0); Out.Ln;
  Out.Int(RBinarySearch(List, 65, 0, LEN(List)-1),0); Out.Ln;
END BS.