判断素数

# include <iostream>
# include <cmath>
using namespace std;

bool Isprimer(int n)
{
    int sqr = sqrt(n * 1.0);
    for(int i = 2; i <= sqr; i++)
    {
        if(n % i == 0)
        return false;
    }
    return true;
}

int main()
{
    int n;
    while(cin >> n)
    {
        if(Isprimer(n))
        cout << "Yes" << endl;
        else
        cout << "No" << endl;
    }
    return 0;
}