import java.util.*;

public class Solution {

    /**

     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可

     * 计算两个数之和

     * @param s string字符串 表示第一个整数

     * @param t string字符串 表示第二个整数

     * @return string字符串

     */

    public String solve (String s, String t) {

        //尝试链表+头插法

        LinkedList<Integer> head = new LinkedList<>();

        char[] arrS = s.toCharArray();

        char[] arrT = t.toCharArray();

        int lenS = arrS.length;

        int lenT = arrT.length;

        int leave = 0;

        while(lenS-- > 0 && lenT-- > 0) {

            //char如何转为真正的int-'0'

            int num = leave + Integer.valueOf(arrS[lenS] - '0') + Integer.valueOf(arrT[lenT] - '0');

            head.addFirst(num % 10);

            leave = num / 10;

        }

        while(lenS-- > 0) {

            int num = leave + Integer.valueOf(arrS[lenS] - '0');

            head.addFirst(num % 10);

            leave = num / 10;

        }

        while(lenT-- > 0) {

            int num = leave + Integer.valueOf(arrT[lenT] - '0');

            head.addFirst(num % 10);

            leave = num / 10;

        }

        if (leave > 0) {

            head.addFirst(leave);

        }

        StringBuilder sb = new StringBuilder();

        Iterator iter = head.iterator();

        while(iter.hasNext()) {

            sb.append(iter.next());

        }

        return new String(sb);

    }

}