MagicSpell3

#include<stdio.h>
#include<string.h>
char str[2010];

int max(int a,int b){
    return (a > b ? a : b);
}

int dp[2010][2010];

int cal(int i,int j){
    if(i < 0 || j < 0)return 0;
    if(dp[i][j] != -1)return dp[i][j];
    if(str[i] == str[j] && i != j){
        return cal(i-1,j-1) + 1;
    }
    return dp[i][j] = max(cal(i-1,j),cal(i,j-1));
}

int main()
{
    for(int i = 0 ; i < 2010 ; i ++)for(int j = 0 ; j < 2010 ; j ++)dp[i][j] = -1;
    scanf("%s",str);
    int n = strlen(str);
    printf("%d",cal(n-1,n-1));
    return 0;
}