#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int main() {
    string s;
    cin >> s;
    int len = s.size();
    
    while (len % 2 == 0) {
        int half = len / 2;
        string left = s.substr(0, half);
        string right = s.substr(half, half);
        reverse(right.begin(), right.end());
        
        if (left == right) {
            len = half;
            s = left;
        } else {
            break;
        }
    }
    
    cout << len << endl;
    return 0;
}
/**************************************************************
	Problem: 1134
	User: zhouhongyi
	Language: C++
	Result: Accepted
	Time:15 ms
	Memory:2076 kb
****************************************************************/