杭电 1316 How Many Fibs?

import java.io.*;
import java.util.*;
import java.math.*;
public class Main {
public static void main(String args[])
{
Scanner cin=new Scanner(System.in);
BigInteger f[]=new BigInteger[505];
f[1]=BigInteger.valueOf(1);
f[2]=BigInteger.valueOf(2);
for(int i=3;i<505;i++)
{
f[i]=f[i-1].add(f[i-2]);
}
BigInteger a,b;
while(cin.hasNextBigInteger())
{
a=cin.nextBigInteger();
b=cin.nextBigInteger();
if(a.compareTo(BigInteger.ZERO)==0&&b.compareTo(BigInteger.ZERO)==0)
{
break;
}
int count=0;
for(int i=1;i<505;i++)
{
if(f[i].compareTo(b)>0)
break;
if(f[i].compareTo(a)>=0&&f[i].compareTo(b)<=0)
{
count++;
}
}
System.out.println(count);
}
}
}