Sayyiduna Jabir (may Allah be pleased with him) states: I do not know with how many pebbles the Prophet (peace and blessings be upon him) stoned it.
Ahmad recorded it, and its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الحج / 5575