#include <bits/stdc++.h> //I AK IOI.
using namespace std;

int dp[1 << 10][1 << 10];

int main()
{
	string s;
	cin >> s;
	string t = "";
	int len = s.size();
	for (int i = len - 1; i >= 0; i--)
	{
		t += s[i];
	}
	for (int i = 1; i <= len; i++)
	{
		for (int j = 1; j <= len; j++)
		{
			if (s[i - 1] == t[i - 1])
			{
				dp[i][j] = dp[i - 1][j - 1] + 1;
			}
			else
			{
				dp[i][j] = max(dp[i][j - 1], dp[i - 1][j]);
			}
		}
	}
	cout << len - dp[len][len];
	return 0;
}