poj 2635 The Embarrassed Cryptographer

import java.math.*;
import java.util.*;

public class Main {
public static void main(String[] args)
{
int len=0;
Scanner cin=new Scanner(System.in);
BigInteger prime[]=new BigInteger[80000];
for(int i=2;i<1000010;i++)     //建立素数表
{
int flag=1;
for(int j=2;j*j<=i;j++)
{
if(i%j==0)
{
flag=0;
break;
}
}
if(flag==1)
{
prime[len++]=BigInteger.valueOf(i);
}
}

while(cin.hasNext())
{
BigInteger n,m;
BigInteger a=new BigInteger("0");
n=cin.nextBigInteger();
m=cin.nextBigInteger();

if(n.equals(a)&&m.equals(a))
{
break;
}
int flag=1;
for(int i=0;i<len;i++)
{
if(a.equals(n.mod(prime[i])))  //判断能否被这个素数整除
{
if(m.compareTo(prime[i])==1)     //比较大小
{
flag=0;
System.out.println("BAD "+prime[i]);
break;
}
}
}
if(flag==1)
{
System.out.println("GOOD");
}
}
}
}