Table:
text: 1990–91 Manchester United F.C. season
Cup Winners' Cup
Cup Winners' Cup
Date_ Round Opponents H_A Result_F_A Scorers Attendance
19 March 1991 Quarter-finals Second leg Montpellier A 2 – 0 Blackmore 2`, Bruce 47` ( pen. ) 18000
10 April 1991 Semi-finals First leg Legia Warsaw A 3 – 1 McClair 36`, Hughes 54`, Bruce 67` 20000
24 April 1991 Semi-finals Second leg Legia Warsaw H 1 – 1 Sharpe 28` 44269
15 May 1991 Final Barcelona N 2 – 1 Hughes (2) 68`, 75` 50000

text: 1990–91 Manchester United F.C. season
Cup Winners' Cup
Cup Winners' Cup
Date_ Round Opponents H_A Result_F_A Scorers Attendance
19 September 1990 Round 1 First leg Pécsi Munkás H 2 – 0 Blackmore 9`, Webb 17` 28411
3 October 1990 Round 1 Second leg Pécsi Munkás A 1 – 0 McClair 77` 17000
23 October 1990 Round 2 First leg Wrexham H 3 – 0 McClair 40`, Bruce 42` ( pen. ), Pallister 59` 29405
7 November 1990 Round 2 Second leg Wrexham A 2 – 0 Robins 31`, Bruce 35` 13327
6 March 1991 Quarter-finals First leg Montpellier H 1 – 1 McClair 1` 41942

Question: What is the lowest Manchester United FC attendance in 1990/91 season when h/AH are cup winners in cup semi-final second leg?