#include <bits/stdc++.h>

#define up(i,l,r) for(int i = (l);i <= (r); i++)

using namespace std;

int f[][];

char s[];

int main()

{

//    freopen("color.in","r",stdin);

    memset(f,0x7F,sizeof(f));

    scanf("%s",s + );

    int n = strlen(s + );

    up(i,,n) f[i][i] = ;

    up(L,,n - )

        for(int i = ,j = i + L; j <= n;i++,j++)

        {

            if(s[i] == s[j]) f[i][j] = min(f[i + ][j],f[i][j - ]);

            else up(k,i,j - ) f[i][j] = min(f[i][j],f[i][k] + f[k + ][j]);

        }

    printf("%d",f[][n]);

    return ;

}