T582463 「2025 扬大ACM选拔赛」I - Last Problem

This ACM-ICPC contest contains 9 problems, labeled sequentially with the English letters $\text{A, B, C, D, E, F, G, H, I}$. Cirno participated in this contest, and she has a total of $n$ accepted submissions $a_1, a_2, \ldots, a_n$. Each accepted submission solved the problem $a_i$. Please determine **how many distinct problems Cirno solved**.

**There are multiple test cases.** The first line of the input contains one integer $T$ ($1 \le T \le 10$) —— the number of test cases. **For each test case:** The first line contains one integer $n~$ ($1 \le n \le 100$) —— the number of Cirno's accepted submissions. The next line contains $n$ uppercase English characters $a_i~$ ($'\text{A}' \le a_i \le '\text{I}'$) —— the problems solved in each accepted submisson.

**For each test case:** Output a single integer on one line —— the total number of distinct problems Cirno solved.