A coalition of Thai pro-democracy parties, which swept Sunday’s election, is on course to form the next government, its leader Pita Limjaroenrat said, seeknig to quell concerns about its ability to muster enough support to elect him as the prime minister.

The group added two more small parties to the coalition, raising its number in the 500-member House of Representatives to 313, Pita told reporters in Bangkok on Thursday, a day after leaders of the newly-formed alliance met formally.

Pita, leader of the Move Forward Party that won the most seats in the May 14 vote, said parties in the coalition are preparing for different scenarios to mitigate risks of it failing to clear the parliament hurdle. The Harvard-educated Pita requires the backing of a minimum 376 lawmakers in a joint sitting of the lower house and the Senate that will select the new prime minister.

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Pita’s bid to take the top job has faced challenges including opposition from a majority of the members of the Senate, stacked with allies of the pro-military establishment of Prime Minister Prayuth Chan-Ocha, and other conservative parties. Bhumjaithai Party, which came third with 70 seats, ruled out its support for Pita, saying it won’t back a candidate from a party planning to amend the country’s lese majeste law.

But Pita remained defiant on Thursday, saying “we have a lot of momentum and my coalition is taking shape.”

On Move Forward’s controversial stance on changes to the royal insult law, Pita said there were differences among the coalition partners and he remained confident that the parties can reach a consensus on how to proceed on the issue.

Cholnan Srikaew, leader of Pheu Thai that’s linked to influential former Prime Minister Thaksin Shinawatra who lives in exile, said the lese majeste law known as Article 112, wasn’t a deal breaker for the party.

While Move Forward has pledged to amend the lese majeste law, which punishes criticism against King Maha Vajiralongkorn and other members of the royal family, Pheu Thai has maintained that the issue should be settled in parliament.