Number of Provinces

`isConnected` is an `n × n` symmetric matrix where `isConnected[i][j] = 1` means cities `i` and `j` are directly linked. A province is a group of cities connected directly or indirectly. Return the number of provinces. **Example 1:** ``` Input: isConnected = [[1, 1, 0], [1, 1, 0], [0, 0, 1]] Output: 2 ``` **Example 2:** ``` Input: isConnected = [[1, 0, 0], [0, 1, 0], [0, 0, 1]] Output: 3 ``` **Example 3:** ``` Input: isConnected = [[1]] Output: 1 ```