#include <bits/stdc++.h>
#include <cstdint>
#include <sys/time.h>

typedef std::int_fast32_t  s32;
typedef std::uint_fast32_t u32;
typedef std::int_fast64_t  s64;
typedef std::uint_fast64_t u64;

const unsigned long mod = 1000000007;

std::string str;

bool check(int begin, int end2) {
  for(int i = begin; i <= end2; ++i) {
    if( str[i] != str[begin + end2 - i] ) return false;
  }
  return true;
}

bool ispa[64][64];
int N;

int memo[64];

int dfs(int begin, int max) {
  if( ispa[begin][N-1] ) return std::max(max, N-1-begin+1);
  if( memo[begin] >= max ) return memo[begin];
  for(int next = N-2; next >= begin; --next) {
    if( ispa[begin][next] ) {
      max = std::max(max, next - begin + 1);
      max = std::max(max, dfs(next+1, max));
    }
  }
  memo[begin] = max;
  return max;
}

int main() {

  std::cin >> str;
  std::vector<std::string> vstr;
  N = str.size();

  for(int i = 0; i < 64; ++i) {
    memo[i] = -1;
  }

  for(int i = 0; i < N; ++i) {
    for(int j = i; j < N; ++j) {
      ispa[i][j] = check(i, j);
    }
  }
  ispa[0][N-1] = false;

  std::cout << dfs(0, 0) << std::endl;
    
  return 0;
}