

#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
char in[105],len;
int dp[105][105];
int main()
{
cin>>in;
len=strlen(in);
for(int i=0;i<len;i++)dp[i][i]=1;
for(int length=2;length<=len;length++)
{
for(int l=0;l<len;l++)//**l 0~总长度
{
int r=l+length-1;
if(r>=len)break;
dp[l][r]=0x3f3f3f3f;
if(in[l]==in[r])
{
dp[l][r]=min(dp[l+1][r],min(dp[l][r-1],length>2?dp[l+1][r-1]+1:dp[l][r-1]));
}
else{
for(int k=l;k<r;k++)
{
dp[l][r]=min(dp[l][r],dp[l][k]+dp[k+1][r]);
}
}
}
}
cout<<dp[0][len-1]<<endl;
return 0;
}