force 1.
state 1. no bitch
state 2. one bitch 第一个bitch的出现可能是偶然，比如一个怨妇出墙，或者某女被
强奸
state 3. man likes the bitch --> an affair with the bitch --> man not
reliable
state 4. the extra bitch
state 5. more men attracted by the extra bitch, become not reliable --> more
bitch
state 6. go back to state 5.
force 2.
state 1. no good girl
state 2. one good girl 第一个good girl的出现可能是偶然，比如一个bitch从良
state 3. man likes the good girl --> married --> man reliable
state 4. the extra good girl
state 5. more men attract
