We are given a random permutation of {1,2,...,n}. We perform bubble sort on it. What is the probability that after single round of bubble sort we get the right (sorted) order? Examples:

1. For [5,1,2,3,4]: 5,1,2,3,4 → 1,5,2,3,4 → 1,2,5,3,4 → 1,2,3,5,4 → 1,2,3,4,5. After the first round of bubble sort, the order is right.
2. For [1,2,5,4,3]: 1,2,5,4,3 → 1,2,4,5,3 → 1,2,4,3,5. After the first round of bubble sort, the order is still not right.