UVA - 10013 - Super long sums

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

public class Main {

    public static void main(String[] args) throws IOException  {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        int cases=Integer.parseInt(br.readLine());
        String m="";
        StringBuilder lol;
        StringBuffer sb=new StringBuffer("");
        short[] num1,num2;
        for(int i=0;i<cases;i++){
            lol=new StringBuilder("");
            if(i>0)
                sb.append("\n");
            br.readLine();
            int block=Integer.parseInt(br.readLine());
            num1=new short[block+1];
            num2=new short[block+1];
            for(int j=0;j<block;j++){
                String str=br.readLine();
                num1[j]=(short) (str.charAt(0)-48);
                num2[j]=(short) (str.charAt(2)-48);
            }
            short carry=0;
            short rem=0;
            short temp=0;
            for(int j=block-1;j>-1;j--){
                temp=(short) (num1[j]+num2[j]+carry);
                carry=(short) (temp/10);
                rem=(short) (temp%10);
                lol.append((char) (rem+48));
            }
            if(carry>0)
                 lol.append((char) (carry+48));
            lol=lol.reverse();
            sb.append(lol).append("\n");
        }
        System.out.print(sb);
    }
}