Min cost Max Flow - Codeforces

#	User	Rating
1	tourist	3880
2	jiangly	3669
3	ecnerwala	3654
4	Benq	3627
5	orzdevinwang	3612
6	Geothermal	3569
6	cnnfls_csy	3569
8	jqdai0815	3532
9	Radewoosh	3522
10	gyh20	3447

#	User	Contrib.
1	awoo	161
2	maomao90	160
3	adamant	156
4	maroonrk	153
5	atcoder_official	148
5	-is-this-fft-	148
5	SecondThread	148
8	Petr	147
9	nor	144
10	TheScrasse	142

Problem Link:Here

I have already solved this problem using Dp.
But in Tag I have seen that it can be solved with Min cost Max flow.
Give some Hints how can i solve this problem using Min cost Max flow.
Thanks in Adavance

uttom's blog