백준 14656 조교는 새디스트야!!

https://www.acmicpc.net/problem/14656

14656번: 조교는 새디스트야!!

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int N = Integer.parseInt(br.readLine());
        StringTokenizer st = new StringTokenizer(br.readLine());
        int[] arr = new int[N];
        for (int i = 0; i < N; i++) {
            arr[i] = Integer.parseInt(st.nextToken());
        }
        int cnt = 0;
        for (int i = 0; i < N; i++) {
            if (arr[i] != (i+1)) cnt++;
        }
        System.out.println(cnt);
    }
}