Java :

import java.util.Scanner;

public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String n = sc.nextLine();
        char c;
        int c1 = 0;
        String s2;
        String s1 = n.toUpperCase();
        ;
        String[] s = s1.split(" ");
        String x = "BUG";
        for (int i = 0; i < s.length; i++) {
            c = s1.charAt(i);
            s2 = s + "";
            if (x.equals(s[i])) {
                c1++;
            }
            //    System.out.print(s[i]+" ");
        }
        System.out.print(c1);
    }
}