Write nth_prime(n) that returns the n-th prime number, counting from 2 as the 1st.
Examples
Input: n = 1
Output: 2
Input: n = 6
Output: 13
Input: n = 100
Output: 541
Constraints
1 <= n <= 2000
Goals
- Reuse a prime test inside a search loop
- Count matches until the n-th one appears