Ahead of the UPA-Left committee meeting, External Affairs Minister Pranab Mukherjee and RJD chief Lalu Prasad on Wednesday met Prime Minister Manmohan Singh and are understood to have discussed a formula to resolve the deadlock over the Indo-US nuclear deal issue.Mukherjee and Prasad drove to Singh's residence about an hour before the UPA-Left meeting and were there for over 45-minutes.During the meeting, a formula aimed at ending the deadlock over the nuclear deal is understood to have been discussed.The formula is believed to be aimed at suggesting ways to placate the Left parties, which are opposed to the deal, so that the government could survive.Soon after meeting with the Prime Minister, Mukherjee and Prasad headed straight for the meeting of the UPA-Left committee at the External Affairs Minister's residence during which the formula would be considered.It was the second meeting that Mukherjee had with the Prime Minister during the day.