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In the years that followed, Eisenhower increased the number of U.S. military advisors in South Vietnam to 900 men. This was due to North Vietnam's support of "uprisings" in the south and concern the nation would fall. In May 1957 Diem, then President of South Vietnam, made a state visit to the United States for ten days. President Eisenhower pledged his continued support, and a parade was held in Diem's honor in New York City. Although Diem was publicly praised, in private Secretary of State John Foster Dulles conceded that Diem had been selected because there were no better alternatives.

How many days did the President of South Vietnam visit the US for in 1957?
ten