CONST
  NMax = 250;
VAR
  Route : ARRAY[1..NMax, 1..NMax] OF LongInt;
  Used : ARRAY[1..NMax] OF Boolean;
  Path : ARRAY[0..NMax] OF Integer;
  N, M, I, T, H, Count : LongInt;
  Found : Boolean;

  PROCEDURE DSF(Start, C : LongInt);
  VAR
    I : LongInt;
  BEGIN
    Used[C] := True;
    IF (Route[C, Start] = 2) THEN
      BEGIN
        Found := True;
        Used[C] := False;
        Exit;
      END;
    FOR I := 1 TO N DO
      IF (NOT Used[I]) AND (Route[C, I] = 2) THEN
        BEGIN
          Route[C, I] := 0;
          Route[I, C] := 0;
          DSF(Start, I);
          Route[C, I] := 2;
          Route[I, C] := 2;
          IF Found THEN Break;
        END;
    IF (NOT Found) THEN
      IF (Route[C, Start] = 1) THEN
        BEGIN
          Route[Start, C] := 2;
          Route[C, Start] := 2;
          Found := True;
        END;
    IF NOT Found THEN
      FOR I := 1 TO N DO
        IF (NOT Used[I]) AND (Route[C, I] = 1) THEN
          BEGIN
            Route[C, I] := 0;
            Route[I, C] := 0;
            DSF(Start, I);
            IF Found THEN
              BEGIN
                Route[C, I] := 2;
                Route[I, C] := 2;
                Break;
              END
            ELSE
              BEGIN
                Route[C, I] := 1;
                Route[I, C] := 1;
              END;
          END;
    Used[C] := False;
  END;

  PROCEDURE DSF2(Start, C, Size : LongInt);
  VAR
    I : LongInt;
  BEGIN
    Used[C] := True;
    IF (Route[C, Start] = 1) THEN
      BEGIN
        Found := True;
        Used[C] := False;
        Path[Size] := C;
        Path[0] := Size;
        Exit;
      END;
    FOR I := 1 TO N DO
      IF (NOT Used[I]) AND (Route[C, I] = 1) THEN
        BEGIN
          Route[C, I] := 0;
          Route[I, C] := 0;
          DSF2(Start, I, Size+1);
          Route[C, I] := 1;
          Route[I, C] := 1;
          IF Found THEN
            BEGIN
              Path[Size] := C;
              Break;
            END;
        END;
    IF (NOT Found) THEN
      IF (Route[C, Start] = 2) THEN
        BEGIN
          Route[Start, C] := 1;
          Route[C, Start] := 1;
          Path[Size] := C;
          Path[0] := Size;
          Found := True;
        END;
    IF NOT Found THEN
      FOR I := 1 TO N DO
        IF (NOT Used[I]) AND (Route[C, I] = 2) THEN
          BEGIN
            Route[C, I] := 0;
            Route[I, C] := 0;
            DSF2(Start, I, Size+1);
            IF Found THEN
              BEGIN
                Route[C, I] := 1;
                Route[I, C] := 1;
                Path[Size] := C;
                Break;
              END
            ELSE
              BEGIN
                Route[C, I] := 2;
                Route[I, C] := 2;
              END;
          END;
    Used[C] := False;
  END;

BEGIN
  FillChar(Route, SizeOf(Route), 0);
  FillChar(Used, SizeOf(Used), False);
  ReadLn(N, M);
  FOR I := 1 TO M DO
    BEGIN
      ReadLn(T, H);
      Route[T, H] := 1;
      Route[H, T] := 1;
    END;
  Count := 0;
  FOR T := 1 TO N DO
    FOR
    H := 1 TO N DO
      IF Route[T, H] = 1 THEN
        BEGIN
          Used[T] := True;
          Route[T, H] := 0;
          Route[H, T] := 0;
          Found := False;
          DSF(T, H);
          IF Found THEN
            BEGIN
              Route[T, H] := 2;
              Route[H, T] := 2;
              Inc(Count);
            END
          ELSE
            BEGIN
              Route[T, H] := 1;
              Route[H, T] := 1;
            END;
          Used[T] := False;
        END;
  WriteLn(Count);
  IF Count <> 0 THEN
    BEGIN
      FOR T := 1 TO N DO
        FOR H := 1 TO N DO
          IF Route[T, H] = 2 THEN
            BEGIN
              Used[T] := True;
              Route[T, H] := 0;
              Route[H, T] := 0;
              Found := False;