import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String A = sc.next();
        String B = sc.next();
        String C = A+B;
        int a = C.length();
        int r = 0;
        while(a>0){
            String t = "";
            for(int i=0; i<a; i++){
                t=t+"o";
            }
            if( C.indexOf(t)!=-1 ){
                break;
            }
            a--;
        }
        System.out.println(a);
    }
}