java大数 斐波那契数列

import java.math.BigInteger;
import java.util.Scanner;
public class Main{

public static void main(String[] args) {
Scanner cin=new Scanner(System.in);
while(cin.hasNext()){//remermber
BigInteger num1=cin.nextBigInteger();
BigInteger num2=cin.nextBigInteger();
BigInteger num3=cin.nextBigInteger();
BigInteger num4 = null;
for(int i=4;i<=100;++i){
num4=num1.add(num2).add(num3);
if(i%3==1){
num1=num4;
}else if(i%3==2){
num2=num4;
}else{
num3=num4;
}
}
System.out.println(num4);
}
}

}