Cryptographer's Conundrum Kattis Problem Solution In Java

//Nayeem Shahriar Joy,Applied Physics & Electronic Engineering, University of Rajshahi.
 

import java.util.HashSet;

import java.util.Scanner;

import java.util.Set;

import javax.swing.text.html.HTMLDocument.Iterator; 

 

public class Joy{

public static void main(String[] args) {

Scanner io = new Scanner(System.in);

String s=io.nextLine();

int count=0;

for(int i=0;i<s.length();i++) {

if(!((i%3==0&&s.charAt(i)=='P')||(i%3==1&&s.charAt(i)=='E')||(i%3==2&&s.charAt(i)=='R')))

{

count++;

}

}

System.out.println(count);

}

}