Taksin's first attempt at reunification—an expedition to Phitsanulok in May 1768—was unsuccessful. He captured Phimai at the end of 1768, and was crowned monarch in December 1768. By late 1769, he had defeated Nakhon Si Thammarat. In mid-1770, he finally defeated Phitsanulok, and became the sole ruler of Siam.
Question: How many years did the reunification attempts last?
Answer: 2