Task: Question Understanding
Input (English): Passage: The long border between Burma and China had long been vaguely defined. The Ming dynasty first conquered Yunnan borderlands between 1380 and 1388, and stamped out local resistance by the mid-1440s. The Burmese control of the Shan States  came in 1557 when King Bayinnaung of the Toungoo dynasty conquered all of the Shan States. The border was never demarcated in the modern sense, with local Shan sawbwas  at the border regions paying tribute to both sides. The situation turned to China's favor in the 1730s when the Qing decided to impose a tighter control of Yunnan's border regions while the Burmese authority largely dissipated with the rapid decline of the Toungoo dynasty.
Question: How many years after the Burmese took control of the Shan States did the situation turn to China's favor when the Qing decided to impose a tighter control of Yunnan's border regions while the Burmese authority largely dissipated?
Output (English): number