#include <iostream>
#include <vector>
using namespace std;

int main() {
    string s ;
    cin >>s;
    int a=-1;
    for (int i = 0; i <= s.size(); i++)
    {
        if ((s[i]=='b'||s[i]=='B')&&(s[i+1]=='o'||s[i+1]=='O')&&(s[i+2]=='b'||s[i+2]=='B'))
        {
            a=i;
            break;
        }
    }
    cout<<a;
}