Contest Duration: - (local time) (100 minutes) Back to Home
C - Next Prime /

Time Limit: 2 sec / Memory Limit: 1024 MB

### 問題文

X 以上の素数のうち、最小のものを求めよ。

### 制約

• 2 \le X \le 10^5
• 入力はすべて整数

### 入力

X


### 出力

X 以上の素数のうち、最小のものを出力せよ。

### 入力例 1

20


### 出力例 1

23


20 以上の素数のうち、最小のものは 23 です。

### 入力例 2

2


### 出力例 2

2


X が素数である場合もあります。

### 入力例 3

99992


### 出力例 3

100003


Score: 300 points

### Problem Statement

Find the minimum prime number greater than or equal to X.

### Notes

A prime number is an integer greater than 1 that cannot be evenly divided by any positive integer except 1 and itself.

For example, 2, 3, and 5 are prime numbers, while 4 and 6 are not.

### Constraints

• 2 \le X \le 10^5
• All values in input are integers.

### Input

Input is given from Standard Input in the following format:

X


### Output

Print the minimum prime number greater than or equal to X.

### Sample Input 1

20


### Sample Output 1

23


The minimum prime number greater than or equal to 20 is 23.

### Sample Input 2

2


### Sample Output 2

2


X itself can be a prime number.

### Sample Input 3

99992


### Sample Output 3

100003