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

int main () {
  char s[5001] = "";
  
  int res = 0;
  
  int ans[5001] = {};
  int dp[5000][5001] = {};
  int len = 0;
  
  res = scanf("%s", s);
  len = strlen(s);
  
  for (int i = 0; i < len; i++) {
    dp[i][i] = 1;
    dp[i][i+1] = 1;
  }
  
  for (int i = 1; i < len; i++) {
    for (int j = 0; j < len-i; j++) {
      if (s[j] == s[j+i] && dp[j+1][j+i] > 0) {
        dp[j][j+i+1] = 1;
      }
    }
  }
  
  ans[0] = len;
  for (int i = 0; i < len; i++) {
    for (int j = i+1; j <= len; j++) {
      if (dp[i][j] > 0) {
        int min = ans[i];
        if (min > j-i) {
          min = j-i;
        }
        if (min > ans[j]) {
          ans[j] = min;
        }
      }
    }
  }
  
  printf("%d\n", ans[len]);
  return 0;
}