import java.io.*;
import java.util.*;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
public class Solution {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        Pattern pattern = Pattern.compile("o(?=oo)");
        Matcher matcher = pattern.matcher(scanner.nextLine());
        int count = 0;
        while(matcher.find())   count++;
        System.out.println("Number of matches : "+count);
    }
}

function main() {
    // Enter your code here
    let regexPattern: RegExp = /o(?=oo)/g;
    let testString:string = readLine();
    console.log("Number of matches : " + testString.match(regexPattern).length)
}

var Regex_Pattern = /o(?=oo)/g;	//Do not delete `/` and `/g`.

let Regex_Pattern = /o(?=oo)/g;

(o)(?=oo)