poj 3982 高精度java

import java.io.*;
import java.util.*;
import java.math.*;
public class Main{
public static BigInteger fun(BigInteger a,BigInteger b,BigInteger c)
{
int n=2;
BigInteger x=a,y=b,z=c;
BigInteger ans;
while(n<99)
{
n++;
ans=BigInteger.valueOf(0);
ans=ans.add(y);
ans=ans.add(x);
ans=ans.add(z);
x=y;
y=z;
z=ans;
//System.out.println(ans);
}
return z;
}
public static void main(String[] args)
{
BigInteger a,b,c;
Scanner cin=new Scanner(System.in);
while(cin.hasNext())
{
a=cin.nextBigInteger();
b=cin.nextBigInteger();
c=cin.nextBigInteger();
BigInteger ans=fun(a,b,c);
System.out.println(ans);
}
}
}