import std.stdio, std.string, std.conv;
import std.range, std.algorithm, std.array, std.typecons, std.container;
import std.math, std.numeric, core.bitop;

enum inf3 = 1_001_001_001;
enum inf6 = 1_001_001_001_001_001_001L;
enum mod = 1_000_000_007L;


void main() {
    string s;
    scan(s);
    auto n = s.length.to!int;

    bool check(int x) {
        if (2*x <= n) {
            return true;
        }

        foreach (i ; n - x .. x) {
            if (s[i] != s[n - x]) {
                return false;
            }
        }

        return true;
    }

    int ok = 1, ng = n + 1;

    while (abs(ok - ng) > 1) {
        int mid = (ok + ng) / 2;
        (check(mid) ? ok : ng) = mid;
    }

    writeln(ok);
}










void scan(T...)(ref T args) {
    import std.stdio : readln;
    import std.algorithm : splitter;
    import std.conv : to;
    import std.range.primitives;

    auto line = readln().splitter();
    foreach (ref arg; args) {
        arg = line.front.to!(typeof(arg));
        line.popFront();
    }
    assert(line.empty);
}

void fillAll(R, T)(ref R arr, T value) {
    static if (is(typeof(arr[] = value))) {
        arr[] = value;
    }
    else {
        foreach (ref e; arr) {
            fillAll(e, value);
        }
    }
}
