|Name|Canton|District|Area (km²)|Population (As of 2005)|Date of law|
|---|---|---|---|---|---|
|Diekirch Dikrech|Diekirch|Diekirch|12.42|6,165|24 February 1843|
|Differdange Déifferdeng|Esch-sur-Alzette|Luxembourg|22.18|19,005|4 August 1907|
|Dudelange Diddeleng|Esch-sur-Alzette|Luxembourg|21.38|17,618|4 August 1907|
|Echternach Iechternach|Echternach|Grevenmacher|20.49|4,507|24 February 1843|
|Esch-sur-Alzette Esch-Uelzecht|Esch-sur-Alzette|Luxembourg|14.35|28,000|29 May 1906|
|Ettelbruck Ettelbréck|Diekirch|Diekirch|15.18|7,364|4 August 1907|
|Grevenmacher Gréiwemaacher|Grevenmacher|Grevenmacher|16.48|3,966|24 February 1843|
|Luxembourg City Lëtzebuerg|Luxembourg|Luxembourg|51.46|76,420|24 February 1843|
|Remich Réimech|Remich|Grevenmacher|5.29|2,986|24 February 1843|
|Rumelange Rëmeleng|Esch-sur-Alzette|Luxembourg|6.83|4,495|4 August 1907|
|Vianden Veianen|Vianden|Diekirch|9.67|1,561|24 February 1843|
|Wiltz Wolz|Wiltz|Diekirch|19.37|4,587|24 February 1843|

Question: how many luxembourg cities had a date of law of feb 24, 1843?
Answer: 7