#include<bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

#define ll long long
#define endl '\n'
#define int ll
using namespace std;
using namespace __gnu_pbds;

template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const int N = 2e5+7, P1 = 31, P2 = 37, mod= 1e9 + 7;

int mul(int a, int b) {
    return (1LL * a * b) % mod;
}

int add(int a, int b) {
    a = (a + mod) % mod;
    b = (b + mod) % mod;
    return (a + b) % mod;
}

int fp(int b, int p) {
    if (b == 1 or p == 0)
        return 1;

    int ret = fp(b, p >> 1);
    ret = mul(ret, ret);

    if (p & 1)
        ret = mul(ret, b);

    return ret;
}

ll modInv(ll n) {
    return fp(n, mod - 2);
}

ll fact[N], inv[N];

void pre() {
    fact[0] = inv[0] = 1;
    for (ll i = 1; i < N; i++)
        fact[i] = (fact[i - 1] * i) % mod, inv[i] = fp(fact[i], mod - 2);
}

ll nCr(ll n, ll r) {
    return ((fact[n] * inv[r]) % mod * inv[n - r]) % mod;
}

ll nPr(ll n, ll r) {
    return ((fact[n] * inv[n - r])) % mod;
}
string s;
int dp[105];
int solve(int idx)
{
    if ( idx == s.size()/2)
        return 0;
    if (~dp[idx])
        return dp[idx];

    dp[idx] = 10000;
    if ( s[idx] != s[s.size()-1-idx])
    {
        int ad =(( s.size()-1-idx -idx <= 2) ? 1 : 2);
        dp[idx] = min(dp[idx],ad+solve(idx+1));
    }
    else
    {
        dp[idx] = min(dp[idx] ,solve(idx+1));
        return dp[idx];
    }

    for (int i = idx+1; i < s.size()/2; ++i) {
        if (s[i] != s[s.size()-1-i])
            dp[idx] = min(dp[idx],(i-idx+2)/2 + solve(i+1));
    }
    return dp[idx];
}
void doWork() {
   cin >> s;
    memset(dp,-1,sizeof dp);
   cout << solve(0) << endl;
}

signed main() {
    ios::sync_with_stdio(false);
    cout.tie(nullptr);
    cin.tie(nullptr);
//    freopen("bisector.in","r",stdin);
//    freopen("bisector.out","w",stdout);
    int t = 1;
    // cout << primes.size() << endl;
   // cin >> t;
    while (t--) {
        doWork();
    }
    return 0;
}