hdu 1905 Pseudoprime numbers

#include<stdio.h>
#include<math.h>
#define ll long long
ll mod;
bool Judge(int x)
{
    for(int i=2;i<sqrt(x+0.1);i++)
    {
        if(x%i==0)
            return true;
    }
    return false;
}
ll mult(ll q,ll n)
{
    ll ret=q;
    ll ans=1;
    while(n>0)
    {
        if(n&1)
        {
            ans*=ret;
            ans%=mod;
        }
        ret=(ret*ret)%mod;
        n>>=1;
    }
    return ans;
}
int main()
{
    int p,a;
    while(scanf("%d %d",&p,&a)!=EOF)
    {
        if(p==0&&a==0)break;
        mod=p;//
        if(Judge(p)&&(int)mult(a,p)==a)
            printf("yes\n");
        else printf("no\n");
        //printf("%d %d\n",((int)pow(a,p))%p,a);
    }
    return 0;
}