#include <algorithm>
#include <vector>
#include <cfloat>
#include <string>
#include <cmath>
#include <set>
#include <cstdlib>
#include <map>
#include <ctime>
#include <iomanip>
#include <functional>
#include <deque>
#include <iostream>
#include <cstring>
#include <queue>
#include <cstdio>
#include <stack>
#include <climits>
#include <sys/time.h>
#include <cctype>

using namespace std;

typedef long long ll;

int main() {
  char s[51];
  scanf("%s", s);

  int ans = 0;

  int n = strlen(s);
  for (int i = 0; i < n; i++) {
    for (int j = i; j < n; j++) {
      if (j-i+1 == n) continue;
      bool ok = true;
      for (int p = 0; i+p <= j-p; p++) {
	if (s[i+p] != s[j-p]) {
	  ok = false;
	  break;
	}
      }
      if (ok) {
	ans = max(ans, j-i+1);
      }
    }
  }

  printf("%d\n", ans);
}