As Salamualikum Wa Rahmatullah Wa Barakatuh,
Narrated Ibn 'Umar: Allah's Apostle (allayhee salat wassalam) said: Islam is based on (the following) five (principles): 1. To testify that none has the right to be worshipped but Allah and Muhammad is Allah's Apostle. 2. To offer the (compulsory congregational) prayers dutifully and perfectly. 3. To pay Zakat (i.e. obligatory charity) . 4. To perform Hajj. (i.e. Pilgrimage to Mecca) 5. To observe fast during the month of Ramadan.
Note: Al-Hajj has Preceded fasting and is agreed upon, i.e that Bukhari and Muslim both agreed upon it and as for fasting preceding Hajj then this occurs in one narration in Sahih Muslim.