At the age of 32, Marshall won Supreme Court of the United States case Chambers v. Florida, 309 U.S. 227 (1940). That same year, he founded and became the executive director of the NAACP Legal Defense and Educational Fund. As the head of the Legal Defense Fund, he argued many other civil rights cases before the Supreme Court, most of them successfully, including Smith v. Allwright, 321 U.S. 649 (1944); Shelley v. Kraemer, 334 U.S. 1 (1948); Sweatt v. Painter, 339 U.S. 629 (1950); and McLaurin v. Oklahoma State Regents, 339 U.S. 637 (1950). His most famous case as a lawyer was Brown v. Board of Education of Topeka, Kansas, 347 U.S. 483 (1954), the case in which the Supreme Court ruled that "separate but equal" public education, as established by Plessy v. Ferguson, was not applicable to public education because it could never be truly equal. In total, Marshall won 29 out of the 32 cases he argued before the Supreme Court.
Question: How many cases did Marshall lose before the Supreme Court?
Answer: 3