Since the 1980s, US farm subsidies for rice, along with copyright and patent issues, have constituted the "major problems in U.S.-Thai trade ties". The rice subsidy was one of the primary obstacles to the negotiation of a bilateral FTA. Approximately two-thirds of Thailand's population are rice farmers, and the U.S. subsidy "severely strains U.S.-Thai relations as Bangkok finds itself unable to explain the income lost to its 35 million rice farmers". USDA-funded research to produce variants of Jasmine rice capable of growing in the US are viewed as biopiracy by many Thai rice farmers. In 2005, Thai rice farmers gathered outside the US embassy to chant a "traditional ritual to bring misfortune to enemies". Farmer protests also occurred outside the US embassy during the 2001 WTO ministerial meeting in Doha. Thai officials "sharply criticized" the Farm Security and Rural Investment Act of 2002, and retaliated by joining two WTO dispute resolution cases against the US: one against anti-dumping subsidy offsets, and the Shrimp-Turtle Case. According to Oxfam, the US spends US$1.3 billion on rice subsidies annually for a crop that costs US$1.8 billion to grow, allowing the US to become the second largest global rice exporter  and dump rice at 34 percent below the cost of production. Following the election of Obama and the 2008 global financial crisis, there are Thai fears of renewed US protectionism.
Question: How many more dollars does it cost to grow the roce crop than the US subsidizes?
Answer: 500000000