Prison orientation consists of being issued clothing, given a handbook of rules, and deloused. Because of overcrowding, prisons usually give about 36 square feet of living space to each inmate and house two to a cell. The three neighborhoods of a prison are the mainline, protective custody, and segregation. Playing by the rules, staying in the mainline, and not making racial slurs will help the inmate survive his term. School is the best aspect of prison, although most prisoners don't take advantage of it. Money is important in prison, although currency is forbidden and an accounting of all money sent to or earned by an inmate is kept in a ledger. Gambling, although prohibited, is widespread. Prisoners should try to stay healthy, since medical attention is not available at night or on weekends and prison doctors often use experimental drugs. Four major gangs hold sway in California's prisons: The Black Guerilla Family, the Aryan Brotherhood, the Nuestra Familia, and the Eme's or the Mexican Mafia. Gangs are involved with prostitution, drug dealing, and protective services within the prison, and their influence extends to the outside. Every conceivable weapon can be found in prison. Food from the prison kitchen is often tainted and contains foreign matter, but the kitchen is still the best place to work. The canteen is the prisoners' salvation where he can buy snacks, cigarettes, tioletries, extra clothes, and appliances. There are good guards, but many harass prisoners who can do nothing but put up with it. Prisoners don't like women guards because they are reminders of the women they left behind, invade the inmates' privacy, are sexually provocative.