// Skyqwq
#include <bits/stdc++.h>

#define pb push_back
#define fi first
#define se second
#define mp make_pair

using namespace std;

typedef long long LL;
typedef pair<int, int> PII;

template <typename T> bool chkMax(T &x, T y) { return (y > x) ? x = y, 1 : 0; }
template <typename T> bool chkMin(T &x, T y) { return (y < x) ? x = y, 1 : 0; }

template <typename T> void inline read(T &x) {
    int f = 1; x = 0; char s = getchar();
    while (s < '0' || s > '9') { if (s == '-') f = -1; s = getchar(); }
    while (s <= '9' && s >= '0') x = x * 10 + (s ^ 48), s = getchar();
    x *= f;
}

const int N = 8e6 + 5;

char s[N], g[N];

int n, m, p[N];

void inline manacher() {
	int r = 0, mid = 0;
	for (int i = 1; i <= m; i++) {
		if (i <= r) p[i] = min(r - i + 1, p[2 * mid - i]);
		else p[i] = 1;
		while (g[i + p[i]] == g[i - p[i]]) p[i]++;
		if (i + p[i] - 1 > r) r = i + p[i] - 1, mid = i; 
	}
}

int main() {
	scanf("%s", s + 1);
	n = strlen(s + 1);
	g[0] = '?';
	for (int i = 1; i <= n; i++) {
		g[++m] = '#';
		g[++m] = s[i];
	}
	g[++m] = '#';
	g[m + 1] = '&';
	manacher();
	int now = 1;
	for (int i = 1; i <= n; i++) {
		if (i < n && (p[2 * i + 1] - 1) / 2 >= i - now + 1) {
			now = i + 1;
			
			continue;
		}
	}
	int r = n;
	for (int i = n; i >= now; i--) {
		if (i > now && (p[2 * i - 1] - 1) / 2 >= r - i + 1) {
			r = i - 1;
			continue;
		}
	}
	printf("%d\n", r - now + 1);
    return 0;
}