Consider the following statements regarding Madku Island in Chhattisgarh:

1. Madku Island is located on the banks of the Shivnath River, the longest tributary of the Mahanadi River.

2. Archaeologists have discovered prehistoric stone tools, inscriptions in Brahmi and Shankha scripts, and 19 ancient temples on the island.

3. The architectural style of the temples on Madku Island resembles that of the Great Mauryan dynasty.

4. Madku Island hosts an annual Christian fair known as Masihi Mela since 1909.

How many of the above statements are correct?