#include <bits/stdc++.h>

using namespace std;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  string S;
  cin >> S;
  auto f = [](string s) {
    int res = 0;
    for (int i = 0; i < (int)s.size(); i++) {
      if (s[0] != s[i]) break;
      res++;
    }
    return res;
  };
  int res = f(S);
  reverse(S.begin(), S.end());
  cout << min(res - 1, f(S)) << '\n';
  return 0;
}