Return colleges which alumnus are most common working in sub industry.

given a industry, count at which college's alumnus are most common working. The number of industry in mainland China is 141. For example,'银行业','房地产开发与经营','计算机应用服务业' and so on.

sub industry: classification of listed company in mainland China.

A sorted list of colleges.

1. given an industry
2. find people who are working in this industry
3. map people to colleges
4. count the number of colleges.
5. sort colleges.