UVA - 10162 - Last Digit

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuffer sb = new StringBuffer("");
        int []arr=new int[100];
        BigInteger bg=new BigInteger("0");
        for(int i=1;i<100;i++){
            bg=bg.add(BigInteger.valueOf(i).modPow(BigInteger.valueOf(i), BigInteger.valueOf(10)));
            arr[i]=bg.mod(BigInteger.valueOf(10)).intValue();
        }
        while (true) {
            String temp=br.readLine();
            BigInteger num=new BigInteger(temp);
            if(temp.equals("0")){
                break;
            }
            int r=num.mod(BigInteger.valueOf(100)).intValue();
            sb.append(arr[r]).append("\n");
        }
        System.out.print(sb);
    }
}