Jaya Krishna Madhusudhana Jaya Radha
Victory to Lord Krishna, the one who vanquished the demon Madhu and who charms Radha. He is Lord Narayana's incarnattion who moved about in Brindavan and held aloft the Govardhana mountain. That very Lord has incarnated as Lord Sai who now dwells in Parthi.
The notes R2 and D2 are also used occasionally.