#include <bits/stdc++.h>

using i64 = long long;

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    std::string s;
    std::cin >> s;
    
    int n = s.size();
    
    std::vector<int> dp(n + 1);
    dp[0] = n;
    for (int k = 1; k < 2 * n; k++) {
        int l = (k - 1) / 2, r = k - l;
        while (l >= 0 && r <= n) {
            if (s[l] != s[r - 1]) {
                break;
            }
            dp[r] = std::max(dp[r], std::min(dp[l], r - l));
            l--, r++;
        }
    }
    
    std::cout << dp[n] << "\n";
    
    return 0;
}