codevs 1702素数判定2

Miller-Rabin算法实现，但是一直被判题程序搞，输入9999999999得到的结果分明是正确的但是一直说我错

 #include <cstdio>
 #include <cmath>
 #include <cstdlib>
 #include <ctime>

 using namespace std;

 typedef long long LL;
 LL gcd(LL x, LL y)
 {
     if (!y) return x;
     return (y, x%y);
 }
 LL pow(LL a, LL x, LL mod)
 {
     LL ans = ;
     while(x)
     {
         if (x & ) (ans *= a) %= mod;
         (a *= a) %= mod;
         x >>= ;
     }
     return ans;
 }
 bool MRT(LL x)
 {
     if (x == ) return true;
     for (LL i = ; i <= ; ++i)
     {
         LL now = rand()%(x-) + ;
         if (pow(now, x-, x) != ) return false;
     }
     return true;
 }
 int main()
 {
     int n;
     LL x;
     while(scanf("%I64d", &x)!=EOF)
     {
         if(x==)
             printf("No\n");
         else if(x==)
             printf("No\n");
         else
         {
             if (MRT(x))
                 printf("Yes\n");
                else
                 printf("No\n");
         }
     }

     return ;
 }