#include <bits/stdc++.h>

using namespace std;
const int N = 110;
const int INF = 0x3f3f3f3f;
string s;
int f[N][N];

int dfs(int l, int r) {
    if (l == r) return 1;
    if (f[l][r]) return f[l][r];
    int res = INF;

    if (s[l] == s[r]) return dfs(l, r - 1);

    for (int i = l; i < r; i++)
        res = min(res, dfs(l, i) + dfs(i + 1, r));

    return f[l][r] = res;
}

int main() {
    cin >> s;
    cout << dfs(0, s.size() - 1) << endl;
    return 0;
}