UVA - 10943 - How do you add?

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("");
        String m = "";
        BigInteger arr[][] =new BigInteger[101][101];
        for(int i=1;i<101;i++){
            arr[1][i]=BigInteger.valueOf(i);
            arr[i][1]=BigInteger.ONE;
        }
        for(int i=2;i<101;i++){
            for(int j=2;j<101;j++){
                arr[i][j]=arr[i-1][j].add(arr[i][j-1]);
            }
        }
        while (true) {
            String[] str=br.readLine().split(" ");
            int i=Integer.parseInt(str[0]);
            int j=Integer.parseInt(str[1]);
            if(i==0 && j==0)
                break;
            sb.append(arr[i][j].mod(BigInteger.valueOf(1000*1000))).append("\n");
        }
        System.out.print(sb);
    }
}