Count Cross-Group Employee Pairs

You are given `n` employees labeled from `0` to `n - 1` and a list of relationships `relations`, where each pair `[a, b]` means employees `a` and `b` belong to the same group. Group membership is transitive, so if `[0, 1]` and `[0, 2]` are present, then `0`, `1`, and `2` are all in one group. Your task is to count how many unordered pairs of employees `(i, j)` can be formed such that `i` and `j` come from different groups. Example: - `n = 5` - `relations = [[0, 1], [0, 2], [3, 4]]` This creates two groups: `{0, 1, 2}` and `{3, 4}`. The valid cross-group pairs are: - `(0, 3)`, `(0, 4)` - `(1, 3)`, `(1, 4)` - `(2, 3)`, `(2, 4)` So the answer is `6`. Return the total number of valid pairs.