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
     * 
     * @param a string字符串 待计算字符串
     * @return int整型
     */
    public int solve (String a) {
        // write code here
        int maxLen = 0;
        for(int i = 0; i < a.length(); i++){
            for(int j = i + 2; j < a.length() + 1; j+=2){
                StringBuilder sb = new StringBuilder(a.substring(i,j));
//                 if(sb.length() % 2 == 0){
                    int halfIndex = sb.length() / 2;
                    if(sb.substring(0,halfIndex).equals(sb.substring(halfIndex,sb.length())) && sb.length() > maxLen){
                        maxLen = sb.length();
                    }
//                 }
            }
        }
        return maxLen;
    }
}