#include <iostream>
#include <string>

using namespace std;

int main()
{
    string in;
    cin >> in;
    int dist = in.length();

    int l, r;
    if (in.length() % 2)
    {
        l = r = in.length() / 2;
    }
    else
    {
        l = in.length() / 2 - 1;
        r = in.length() / 2;
    }

    while (l > 0 && r < in.length() - 1)
    {
        if (in[l - 1] != in[l])
        {
            dist = in.length() / 2 - l - (in.length() % 2 ? 0 : 1);
            break;
        }
        if (in[r] != in[r + 1])
        {
            dist = r - in.length() / 2;
            break;
        }
        l--;
        r++;
    }
    cout << (in.length() - (in.length() /2 - dist));
}