32번<>

import java.util.Scanner;

public class jar32 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		System.out.println("==== 채점하기 ====");
		String a = sc.next();
		String [] b = a.split("");
		
		int num=0;
		int num1=0;
		
		for(int i=0; i<b.length;i++) {
			if(b[i].equals("O")) {
				num1++;
				num+=num1;
			}else {
				num=0;
			}
		}
		System.out.println(num);
	}
}