// yukicoder: No.273 回文分解
// 2019.4.18 bal4u

#include <stdio.h>
#include <string.h>

#if 0
#define gc() getchar_unlocked()
#else
#define gc() getchar()
#endif
int ins(char *s)  // 文字列の入力　スペース以下の文字で入力終了
{
	char *p = s;
	char c;
	do *s++ = '_', c = gc(), *s++ = c;
	while (c > ' ');
	*--s = 0;
	return s - p;
}

int r[105];
char s[105];

void manacher(char *s, int w)
{
	int i = 0, j = 0, k = 1;
	while (i < w) {
		while (i >= j && i + j < w && s[i - j] == s[i + j]) j++;
		r[i] = j;
		k = 1; while (i >= k && i + k < w && k + r[i - k] < j) {
			r[i + k] = r[i - k], k++;
		}
		i += k; j -= k;
	}
}

int main()
{
	int i, j, p, max, w = ins(s);
	for (j = 0; j < 2; j++) {
		max = 0, manacher(s, w);
		for (i = 0; i < w; i++) {
			if (r[i] > max) max = r[i], p = i;
		}
		if (w > 2*max) break;
		w -= 2, s[w] = 0;
		memset(r, 0, sizeof(r));
	}
	printf("%d\n", max-1);
	return 0;
}