# C#LeetCode刷题之#204-计算质数（Count Primes）

Count the number of prime numbers less than a non-negative number, n.

Input: 10

Output: 4

Explanation: There are 4 prime numbers less than 10, they are 2, 3, 5, 7.

```public class Program {

}```

```[0,1]
[0,1]```