请阅读下面这张Markdown格式的表格并回答问题。同一行中不同列的单元格用'|'分隔，不同行的单元格用'
'分隔。

表格标题:
57 图表：重点城市新房成交周数据
表格:
| 城市 | 销售套数05.27-06.02 | 销售套数05.20-05.26 | 销售套数年度周动均态 | 销售套数环比 | 销售套数较周均变化 | 销售面积05.27-06.02 | 销售面积05.20-05.26 | 销售面积年度周动均态 | 销售面积环比 | 销售面积较周均变化 |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 北京 | 1553.0 | 2149 | 1361.0 | -28.0 | 14.0 | 19.5 | 23.8 | 14.5 | -18.0 | 35.0 |
| 上海 | 2361.0 | 1991 | 2241.0 | 19.0 | 5.0 | 26.5 | 22.6 | 22.7 | 17.0 | 17.0 |
| 深圳 | 1490.0 | 1114 | 620.0 | 34.0 | 140.0 | 13.2 | 9.5 | 5.4 | 38.0 | 145.0 |
| 杭州 | 2164.0 | 2172 | 1155.0 | 0.0 | 87.0 | 22.3 | 22.9 | 11.6 | -3.0 | 92.0 |
| 天津 | 1515.0 | 1717 | 1286.0 | -12.0 | 18.0 | 15.9 | 18.1 | 13.5 | -12.0 | 18.0 |
| 南京 | 1115.0 | 1339 | 860.0 | -17.0 | 30.0 | 11.2 | 14.2 | 8.9 | -21.0 | 27.0 |
| 武汉 | 1857.0 | 2353 | 2083.0 | -21.0 | -11.0 | 20.5 | 24.5 | 20.6 | -16.0 | -1.0 |
| 重庆 | 4708.0 | 4688 | 3618.0 | 0.0 | 30.0 | 44.7 | 43.4 | 33.2 | 3.0 | 34.0 |
| 成都 | 2138.0 | 1975 | 1371.0 | 8.0 | 56.0 | 25.0 | 23.8 | 18.3 | 5.0 | 36.0 |
| 青岛 | 2063.0 | None | 1428.0 | None | 44.0 | 19.9 | None | 13.6 | None | 47.0 |
| 苏州 | 3722.0 | 2925 | 1598.0 | 27.0 | 133.0 | 40.0 | 31.4 | 17.4 | 27.0 | 130.0 |
| 无锡 | 1060.0 | 1050 | 572.0 | 1.0 | 85.0 | 13.3 | 12.3 | 6.8 | 8.0 | 96.0 |
| 福州 | 384.0 | 685 | 290.0 | -44.0 | 32.0 | 4.3 | 7.5 | 3.2 | -43.0 | 36.0 |
| 东莞 | 1212.0 | 1230 | 839.0 | -1.0 | 45.0 | 12.7 | 11.9 | 8.8 | 6.0 | 45.0 |
| 厦门 | 912.0 | 1006 | 506.0 | -9.0 | 80.0 | 9.6 | 10.8 | 5.8 | -11.0 | 66.0 |
| 长沙 | 1121.0 | 968 | 812.0 | 16.0 | 38.0 | 12.5 | 10.5 | 8.9 | 19.0 | 40.0 |
| 昆明 | 1855.0 | 1852 | 1215.0 | 0.0 | 53.0 | 16.3 | 13.9 | 10.0 | 17.0 | 63.0 |
| 惠州 | 524.0 | 515 | 451.0 | 2.0 | 16.0 | 6.3 | 6.1 | 5.3 | 2.0 | 19.0 |
| 一线合计 | 7568.0 | 7426 | 5377.0 | 2.0 | 41.0 | 81.5 | 78.9 | 54.1 | 3.0 | 51.0 |
| 二线合计 | 24186.0 | 22677 | 16909.0 | 7.0 | 43.0 | 252.1 | 231.3 | 173.9 | 9.0 | 45.0 |
| 合计 | 30201.0 | 27954 | 20924.0 | 8.0 | 44.0 | 314.0 | 286.4 | 213.6 | 10.0 | 47.0 |
问题:
麻烦请问一下，销售面积环比大于 5并且销售面积较周均变化大于 50的重点城市总共有多少？
Answer:
4