#include "bits/stdc++.h"

const int N = 60;
int n, f[N][N];
char s[N];

int main() {
    freopen("tuse.in", "r", stdin); 
    freopen("tuse.out", "w", stdout);
    
    memset(f, 0x3f, sizeof f);

    std::cin >> s + 1;
    n = strlen(s + 1);

    for (int len = 1; len <= n; ++ len) {
        for (int i = 1; i + len - 1 <= n; ++ i) {
            int j = i + len - 1;
            if (i == j) {
                f[i][j] = 1;
            } else if (s[i] == s[j]) {
                f[i][j] = std::min(f[i + 1][j], f[i][j - 1]);
            } 
            for (int k = i; k < j; ++ k) {
                f[i][j] = std::min(f[i][j], f[i][k] + f[k + 1][j]);
            }
        }
    }

    std::cout << f[1][n] << '\n';
    return 0;
}