Answer based on context:

On July 18, 2005, a nonviolent protest was held. The protest began in Netivot near Gaza. The protest march ended July 21 after police prevented protesters from continuing to Gush Katif. On August 2, 2005, another protest against disengagement began in Sderot, with approximately 50,000 attendees. On August 10, 2005, in response to calls from Jewish religious leaders, including former Chief Rabbis Avraham Shapira, Ovadia Yosef, and Mordechai Eliyahu, between 70,000 (police estimate) and 250,000 (organizers estimate) Jews gathered for a rally centered at the Western Wall in prayer to ask that the planned disengagement be cancelled. The crowds that showed up for the rally overwhelmed the Western Walls capacity and extended as far as the rest of the Old City and surrounding Jerusalem neighborhoods. The prayer rally was the largest of its kind for over 15 years, since the opposition to the Madrid Conference of 1991. On August 11, 2005, between 150,000 (police estimates) and 300,000 (organizers estimates) people massed in and around Tel Avivs Rabin Square for an anti-disengagement rally. Organizers called the event "the largest expression of public protest ever held in Israel."  According to a police spokesman, it was one of the largest rallies in recent memory.

How many former Chief Rabbis supported the rally against disengagement?
3