1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashSet;
import java.util.Set;
public class Main{
    static StringBuffer resultStr = new StringBuffer();
    public static void main(String args[]) {
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        int result = 0;
        int setSize = 0;
        Set<String> strs;
        try {
            setSize = Integer.parseInt(bf.readLine());
            strs = new HashSet<>(setSize);
            for (int i = 0; i < setSize; i++) {
                String str = bf.readLine();
                if(strs.size()>0){
                    if(strs.contains(Main.getReverse(str))){
                        result += 1;
                    }
                }
                strs.add(str);
                resultStr.setLength(0);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        System.out.print(result);
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX