1 /**
 2  *  Night gathers, and now my watch begins.
 3  *  It shall not end until my death.
 4  *  I shall take no wife, hold no lands, father no children.
 5  *  I shall wear no crowns and win no glory.
 6  *  I shall live and die at my post.
 7  *  I am the sword in the darkness.
 8  *  I am the watcher on the walls.
 9  *  I am the fire that burns against the cold,
10  *  the light that wakes the sleepers,
11  *  the shield that guards the realms of men.
12  *  I pledge my life and honor to the Night's Watch,
13  *  for this night,
14  *  and all the nights to come.
15  */
16
17 #include<bits/stdc++.h>
18 #define lson i<<2
19 #define rson i<<2|1
20 #define LS l,mid,lson
21 #define RS mid+1,r,rson
22 #define mem(a,x) memset(a,x,sizeof(a))
23 #define gcd(a,b) __gcd(a,b)
24 #define ll long long
25 #define ull unsigned long long
26 #define lowbit(x) (x&-x)
27 #define pb(x) push_back(x)
28 #define enld endl
29 #define mian main
30 #define itn int
31 #define prinft printf
32 #pragma GCC optimize(2)
33 #pragma comment(linker, "/STACK:102400000,102400000")
34
35 const double PI = acos (-1.0);
36 const int INF = 0x3f3f3f3f;
37 const int EXP = 1e-8;
38 const int N = 1e5 + 5;
39 const int MOD = 1e9 + 7;
40 const int MAXN = 1e3 + 20;
41
42 using namespace std;
43
44 string s;   //题目给的原字符串
45 string sr;  //原字符串的翻转字符串
46 int dp[MAXN][MAXN]; //dp[i+1][j+1]状态表示为 (s0 ~ si) 和 (s0 ~ sj) 的LCS
47
48 int main() {
49     cin >> s;
50     mem (dp, 0);    //dp数组初始化
51     sr = s;
52     reverse (sr.begin(), sr.end()); //构造翻转串
53     for (itn i = 1; i <= s.size(); ++i)
54         for (int j = 1; j <= sr.size(); ++j)
55             if (s[i - 1] == sr[j - 1])
56                 dp[i][j] = dp[i - 1][j - 1] + 1;
57             else
58                 dp[i][j] = max (dp[i - 1][j], dp[i][j - 1]);
59     cout << s.size() - dp[s.size()][sr.size()] << endl; //ans = s的长度 - LCS(s, sr)
60     return 0;
61 }