San Francisco's best-known madam was sentenced yesterday to 90 days in a nunnery.

Marlene "Brandy" Baldwin, 39, who has had run-ins with police vice officers for more than a decade, pleaded no contest to a charge of pandering. The sentence followed a police raid late last year at a popular bordello in a Tudor-style house in one of this city's finer neighborhoods.

Yesterday, Superior Court Judge Daniel Hanlon, who reviewed Baldwin's probation report and "took into consideration reports of her health," altered a sentence of 90 days in jail to 90 days at the Convent of the Good Shepherd.

Baldwin, the judge explained later, faces orthopedic surgery as the result of her attempted seven years ago to escape a police raid on another bordello by jumping out of a second-story window.

The judge ordered her into the custody of Sister Jane, a convent social worker. Baldwin also was placed on probation for three years.

Hanlon said he did not know "if we'll ever be able to change [Baldwin's] attitude about prostitution. But I do intend for her not to operate in this town, at least for the next three years."

The nunnery she was ordered to, one of 486 Good Shepherd convents in the world, provides a cottage for women sentenced to stay on its premises.

The 10 nuns who live there, "never ask about religion, never ask about money and never ask about problems," according to Mother Superior Columba. "We ask, 'Do you think we can help?'"

Women sentenced to stay at the convent are given an opportunity for job training, or a new job. They are not required to participate in religious services.

The "street gals," as the mother superior refers to them, are encouraged "to profit by their mistakes."

The women are expected to follow convent rules, but are free to leave the convent. However, if they do, probation officers and the courts are notified. c

Baldwin reportedly was getting settled at the convent and was taking no telephone calls.