itsa基 8 質數判別

#include <iostream>
using namespace std;

int main ()
{
int n,a,ans;
cin >> n;
ans = 1;
a = 2;
while (a < n)
{
if (n % a == 0)
{
ans = 0;
}
a++;
}
if (ans == 1)
{
cout << "YES" << endl;
}
else
{
cout << "NO" << endl;
}
return 0;
}