program F;
{$APPTYPE CONSOLE}
uses
  SysUtils;

const cX1 =  1 ; cX2 =  2 ; cY1 =  3 ; cY2 =  4 ;

type
  ARR = array[byte] of record
    Value : comp;
    Mode  : byte;
    Parent : byte;
  end;

var
  ARRX, ARRY : ARR;
  IX, IY : byte;
  NX, NY : byte;
  NN, I, J, K  : byte;
  SQUARE : array[ 1 .. 4 ] of array[byte] of byte;
  X1, Y1, X2, Y2 : longint;
  VIS : array[byte] of array[byte] of byte;
  P : comp;

begin
// PART  1  : We should read squares
  AssignFile(input, 'input.txt');
  Reset(input);
  AssignFile(output, 'output.txt');
  Rewrite(output);
  NN :=  0 ;
  Read(X1, Y1, X2, Y2);
  with ARRX[IX] do begin
    Value := X1;
    Mode := cX1;
    Parent :=  0 ;
  end;
  with ARRX[IX+ 1 ] do begin
    Value := X2;
    Mode := cX2;
    Parent :=  0 ;
  end;
  with ARRY[IY] do begin
    Value := Y1;
    Mode := cY1;
    Parent :=  0 ;
  end;
  with ARRY[IY+ 1 ] do begin
    Value := Y2;
    Mode := cY2;
    Parent :=  0 ;
  end;
  Inc(IX, 2 );
  Inc(IY, 2 );
// PART  2  : reading small rectangles
  Read(NN);
  for I :=  1  to NN do begin
    Read(X1, Y1, X2, Y2);
    with ARRX[IX] do begin
      Value := X1;
      Mode := cX1;
      Parent := I;
    end;
    with ARRX[IX+ 1 ] do begin
      Value := X2;
      Mode := cX2;
      Parent := I;
    end;
    with ARRY[IY] do begin
      Value := Y1;
      Mode := cY1;
      Parent := I;
    end;
    with ARRY[IY+ 1 ] do begin
      Value := Y2;
      Mode := cY2;
      Parent := I;
    end;
    Inc(IX, 2 );
    Inc(IY, 2 );
  end;
// PART  3  : Sort ARRX and ARRY
  for I :=  0  to IX- 2  do begin
    for J := I+ 1  to IX- 1  do begin
      if( ARRX[I].Value > ARRX[J].Value) then begin
        move(ARRX[I], ARRX[ 255 ], sizeof(ARRX[ 0 ]));
        move(ARRX[J], ARRX[I], sizeof(ARRX[ 0 ]));
        move(ARRX[ 255 ], ARRX[J], sizeof(ARRX[ 0 ]));
      end;
    end;
  end;
  for I :=  0  to IY- 2  do begin
    for J := I+ 1  to IY- 1  do begin
      if( ARRY[I].Value > ARRY[J].Value) then begin
        move(ARRY[I], ARRY[ 255 ], sizeof(ARRY[ 0 ]));
        move(ARRY[J], ARRY[I], sizeof(ARRY[ 0 ]));
        move(ARRY[ 255 ], ARRY[J], sizeof(ARRY[ 0 ]));
      end;
    end;
  end;
// PART  4  : Convert float coordinates to indexed
  for I :=  0  to IX- 1  do begin
    SQUARE[ARRX[I].Mode][ARRX[I].Parent] := I;
    SQUARE[ARRY[I].Mode][ARRY[I].Parent] := I;
  end;
// PART  5  : Fill visibility array
  fillchar(VIS, sizeof(VIS),  0 );
  for I := SQUARE[cX1][ 0 ] to SQUARE[cX2][ 0 ]- 1  do begin
    for J := SQUARE[cY1][ 0 ] to SQUARE[cY2][ 0 ]- 1  do begin
      VIS[I][J] :=  1 ;
    end;
  end;
  for K :=  1  to NN do begin
    for I := SQUARE[cX1][K] to SQUARE[cX2][K]- 1  do begin
      for J := SQUARE[cY1][K] to SQUARE[cY2][K]- 1  do begin
        VIS[I][J] :=  0 ;
      end;
    end;
  end;
// PART  6  : Calculate area
  for I :=  0  to IX- 2  do begin
    for J :=  0  to IY- 2  do begin
      if(VIS[I][J] =  1 ) then begin
        P := P + (ARRX[I+ 1 ].Value - ARRX[I].Value) *
                 (ARRY[J+ 1 ].Value - ARRY[J].Value);
      end;
    end;
  end;
  Write(P: 0 : 0 );
  CloseFile(output);
end.