What does the 235 package link mechanism mean?

According to the proportion of provincial public security department 20%, municipal public security bureau 30% and county (city, district) public security bureau 50%. The contract system is the working mechanism for leading cadres at the county level to contract in townships and villages (communities). In view of the relevant situation, the relevant person in charge of the Provincial Public Security Department said that it is necessary to further refine the guarantee mechanism of the "235" organ in combination with the requirements of practical activities, that is, according to the proportion of 20% of the Provincial Public Security Department, 30% of the Municipal Public Security Bureau and 50% of the county (city, district) public security (sub-bureau). Realize the full coverage of 1504 police station, and walk all the time every month to promote the normalization of government affairs and police affairs.