#include <bits/stdc++.h>
using namespace std;
template <class A>
void pr(A a) {
  cout << a;
  cout << '\n';
}
template <class A, class B>
void pr(A a, B b) {
  cout << a << ' ';
  pr(b);
}
template <class A, class B, class C>
void pr(A a, B b, C c) {
  cout << a << ' ';
  pr(b, c);
}
template <class A, class B, class C, class D>
void pr(A a, B b, C c, D d) {
  cout << a << ' ';
  pr(b, c, d);
}
template <class A>
void PR(A a, long long n) {
  for (long long i = (long long)(0); i < (long long)(n); i++) {
    if (i) cout << ' ';
    cout << a[i];
  }
  cout << '\n';
}
long long check(long long n, long long m, long long x, long long y) {
  return x >= 0 && x < n && y >= 0 && y < m;
}
const long long MAX = 1000000007, MAXL = 1LL << 61, dx[4] = {-1, 0, 1, 0},
                dy[4] = {0, 1, 0, -1};
void Main() {
  string s;
  cin >> s;
  long long n = s.size();
  long long d[26][n + 1];
  vector<long long> v[26];
  memset(d, 0, sizeof(d));
  for (long long i = (long long)(0); i < (long long)(n); i++) {
    d[s[i] - 'a'][i + 1]++;
    v[s[i] - 'a'].push_back(i);
  }
  for (long long j = (long long)(0); j < (long long)(26); j++) {
    for (long long i = (long long)(0); i < (long long)(n); i++)
      d[j][i + 1] += d[j][i];
  }
  long long dp[2][n + 1];
  for (long long i = (long long)(0); i < (long long)(2); i++)
    fill(dp[i], dp[i] + n + 1, MAX);
  dp[0][0] = dp[1][n] = 0;
  long long c[26], cnt = 0;
  memset(c, 0, sizeof(c));
  for (long long i = (long long)(0); i < (long long)(n); i++) {
    int x = s[i] - 'a';
    c[x] ^= 1;
    if (c[x])
      cnt++;
    else
      cnt--;
    if (cnt <= 1) {
      dp[0][i + 1] = min(dp[0][i + 1], dp[0][0] + 1);
      if (dp[1][i + 1] != MAX) {
        pr(dp[0][i + 1] + dp[1][i + 1]);
        return;
      }
    }
  }
  memset(c, 0, sizeof(c));
  cnt = 0;
  for (int i = n - 1; i >= 0; i--) {
    int x = s[i] - 'a';
    c[x] ^= 1;
    if (c[x])
      cnt++;
    else
      cnt--;
    if (cnt <= 1) {
      dp[1][i] = min(dp[1][i], dp[1][n] + 1);
      if (dp[0][i] != MAX) {
        pr(dp[0][i] + dp[1][i]);
        return;
      }
    }
  }
  for (long long k = (long long)(1); k < (long long)(n); k++) {
    if (dp[0][k] == MAX) continue;
    cnt = 0;
    memset(c, 0, sizeof(c));
    for (long long i = (long long)(k); i < (long long)(n); i++) {
      int x = s[i] - 'a';
      c[x] ^= 1;
      if (c[x])
        cnt++;
      else
        cnt--;
      if (cnt <= 1) {
        dp[0][i + 1] = min(dp[0][i + 1], dp[0][k] + 1);
        if (dp[1][i + 1] != MAX) {
          pr(dp[0][i + 1] + dp[1][i + 1]);
          return;
        }
      }
    }
  }
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  Main();
  return 0;
}
