#include <algorithm>
#include <cstdio>
#include <cstring>
#include <stack>
using namespace std;
const int kMaxN = 4e6 + 10;
char s[kMaxN], s_reverse[kMaxN];
int len = 0;
int Next[kMaxN];
int main() {
#ifdef local
  freopen("pro.in", "r", stdin);
#endif
  scanf("%s", s + 1);
  len = strlen(s + 1);
  for (int i = 1; i <= len; i++) s_reverse[i] = s[len + 1 - i];
  for (int i = 2, j = 0; i <= len; i++) {
    while (j > 0 && s_reverse[i] != s_reverse[j + 1]) j = Next[j];
    if (s_reverse[i] == s_reverse[j + 1]) j++;
    Next[i] = j;
  }
  int p = 0;
  for (int i = 1; i <= len; i++) {
    while (p > 0 && s[i] != s_reverse[p + 1]) p = Next[p];
    if (s[i] == s_reverse[p + 1]) p++;
  }
  printf("%d\n", len - p);
  return 0;
}