#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <math.h>
#define REP(i, n) for (ll i = 0; i < n; i++)
#define REP1(i, n) for (ll i = 1; i <= n; i++)
#define RREP(i, n) for (ll i = n - 1; i >= 0; i--)
#define RREP1(i, n) for (ll i = n; i >= 1; i--)
#define FOR(i, a, b, c) for (ll i = a; i <= b; i += c)
#define RFOR(i, a, b, c) for (ll i = a; i >= b; i -= c)
#define MAX(a, b) (a > b ? a : b)
#define MIN(a, b) (a < b ? a : b)
#define INF 1145141919
typedef long long ll;

char s[51];

bool check(int head, int last) {
    FOR(i, 0, (last - head + 1) / 2 - 1, 1)
        if (s[head + i] != s[last - i]) return false;
    return true;
}

int main() {
    scanf("%s", s);
    int len = strlen(s);
    int max = 0;
    REP1(i, len - 1) FOR(j, i, len - 1, 1)
        if (check(i, j)) max = MAX(max, j - i + 1);
    REP(i, len - 1) FOR(j, i, len - 2, 1)
        if (check(i, j)) max = MAX(max, j - i + 1);
    printf("%d\n", max);
    return 0;
}