#include "bits/stdc++.h"
#define rep(i, a, n) for (auto i = a; i <= (n); ++i)
#define revrep(i, a, n) for (auto i = n; i >= (a); --i)
#define all(a) a.begin(), a.end()
#define sz(a) (int)(a).size()
template<class T> inline bool chmax(T &a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T &a, T b) { if (b < a) { a = b; return 1; } return 0; }
using namespace std;
 
template<class A, class B> string to_string(pair<A, B> p);
string to_string(const string &s) { return '"' + s + '"'; }
string to_string(const char *s) { return to_string((string) s); }
string to_string(char c) { return "'" + string(1, c) + "'"; }
string to_string(bool x) { return x ? "true" : "false"; }
template<class A> string to_string(const A &v) {
	bool first = 1;
	string res = "{";
	for (const auto &x: v) {
		if (!first) res += ", ";
		first = 0;
		res += to_string(x);
	}
	res += "}";
	return res;
}
template<class A, class B> string to_string(pair<A, B> p) { return "(" + to_string(p.first) + ", " + to_string(p.second) + ")"; }
 
void debug_out() { cerr << endl; }
template<class H, class... T> void debug_out(const H& h, const T&... t) {
	cerr << " " << to_string(h);
	debug_out(t...);
}
#ifndef ONLINE_JUDGE
	#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
	#define debug(...) if(0) puts("No effect.")
#endif
 
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vvi = vector<vi>;

template<class T>
vi Manacher(const T &s) {
	int n = sz(s), j = 0;
	vi len(n * 2 - 1, 1);
	rep(i, 1, n * 2 - 2) {
		int p = i / 2, q = i - p, r = (j + 1) / 2 + len[j] - 1;
		len[i] = r < q ? 0 : min(r - q + 1, len[j * 2 - i]);
		while (p > len[i] - 1 && q + len[i] < n && s[p - len[i]] == s[q + len[i]]) len[i]++;
		if (q + len[i] - 1 > r) j = i;
	}
	return len;
}

int main() {
	ios::sync_with_stdio(0); cin.tie(0);
	
	string s; cin >> s;
	auto rs = Manacher(s);
	auto check = [&](int l, int r) {
		int len = r - l + 1;
		int rad = rs[l + r];
		return len <= rad * 2;
	};
	int l = 0, r = sz(s) - 1, len = 2;
	while (len <= r - l + 1) {
		if (check(l, l + len - 1)) {
			l += len / 2;
			len = 2;
			continue;
		}
		if (check(r - len + 1, r)) {
			r -= len / 2;
			len = 2;
			continue;
		}
		len += 2;
	}
	int ans = r - l + 1;
	printf("%d\n", ans);
	return 0;
}