Problem:
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

Solution in Pascal (FPC 3.0.4) (judge verdict: Accepted)

program main;
var 
    a : QWord;
    i : integer;
    check : boolean;
    final : boolean;
begin
    final := false;
    readln(a);
    while final = false do
        begin
            check := false;
            for i := 2 to a-1 do 
                if (( a mod i ) = 0) then 
                    check := true;
            if check = false then 
                final := true;
            if check = true then 
                inc(a);
        end;
        writeln(a);
end.