int getless(int temp) {
int l = 1, r = maxp_num;
while (l < r) {
int mid = (l + r) / 2;
if (prime[mid] > temp) {
r = mid - 1;
}
else if (prime[mid] == temp)
{
break;
}
else {
l = mid + 1;
}
}
int mid = (l + r) / 2;
//cout << a[mid]<<endl;
if (prime[mid] > temp) {
mid--;
}
return mid;
}