import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;

public class Main  {

    public static void main(String[] args) throws Exception{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] normal = br.readLine().split("");
        String[] reverse = new String [normal.length];
        int swap = 0;
        for(int i=0;i<normal.length;i++){
            reverse[i] = normal[normal.length-i-1];
        }

        out: for(int i=0;i<normal.length;i++){
            if(normal[i].equals(reverse[i])){
                continue out;
            }
            else{
                for(int x=i+1;x<normal.length;x++){
                    if(normal[x].equals(reverse[i])){
                        for(int b = i+1;b<=x;b++) {
                            normal[b] = normal[b - 1];
                            swap++;
                        }
                        normal[i] = reverse[i];
                        continue out;
                    }
                }
            }
        }
        System.out.println (swap);

    }


}